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2017
Rowell, TJ, Demer DA, Aburto-Oropeza O, Cota-Nieto JJ, Hyde JR, Erisman BE.  2017.  Estimating fish abundance at spawning aggregations from courtship sound levels. Scientific Reports. 7:3340.   10.1038/s41598-017-03383-8   Abstract

Sound produced by fish spawning aggregations (FSAs) permits the use of passive acoustic methods to identify the timing and location of spawning. However, difficulties in relating sound levels to abundance have impeded the use of passive acoustics to conduct quantitative assessments of biomass. Here we show that models of measured fish sound production versus independently measured fish density can be generated to estimate abundance and biomass from sound levels at FSAs. We compared sound levels produced by spawning Gulf Corvina (Cynoscion othonopterus) with simultaneous measurements of density from active acoustic surveys in the Colorado River Delta, Mexico. During the formation of FSAs, we estimated peak abundance at 1.53 to 1.55 million fish, which equated to a biomass of 2,133 to 2,145 metric tons. Sound levels ranged from 0.02 to 12,738 Pa2, with larger measurements observed on outgoing tides. The relationship between sound levels and densities was variable across the duration of surveys but stabilized during the peak spawning period after high tide to produce a linear relationship. Our results support the use of active acoustic methods to estimate density, abundance, and biomass of fish at FSAs; using appropriately scaled empirical relationships, sound levels can be used to infer these estimates.

Erisman, BE, Cota-Nieto JJ, Moreno-Baez M, Aburto-Oropeza O.  2017.  Vulnerability of spawning aggregations of a coastal marine fish to a small-scale fishery. Marine Biology. 164   10.1007/s00227-017-3135-8   AbstractWebsite

For marine fishes that form spawning aggregations, vulnerability to aggregation fishing is influenced by interactions between the spatio-temporal patterns of spawning and aspects of the fishery that determine fishing effort, catch, and catch rate in relation to spawning. We investigated the spatio-temporal dynamics of spawning and fishing for the barred sand bass, Paralabrax nebulifer, in Punta Abreojos, Mexico from 2010 to 2012 as a means to assess its vulnerability to aggregation fishing by the local commercial fishery. Monthly, spatial patterns in gonadal development in collected females indicated that adults formed spawning aggregations at two sites in Punta Abreojos during July and August. Monthly patterns in the spatial distribution of fishing matched the spawning behavior of P. nebulifer, with effort and catch concentrated at spawning aggregation sites during those months. However, fishing effort, catch, and catch-per-unit effort did not increase during the spawning season, and fishing activities associated with the spawning season comprised only a small percentage of the total annual effort (22%) and catch (17%).Therefore, while the population of P. nebulifer at Punta Abreojos should be vulnerable to aggregation fishing due to the spatio-temporal dynamics of its spawning aggregations, vulnerability is greatly reduced, because fishing activities are not disproportionately focused on spawning aggregations and fishing methods are not optimized to maximize harvest from the aggregations. Differences between our results and previous studies on aggregation fisheries for P. nebulifer in California, USA, reinforce the importance of assessing factors influencing vulnerability to aggregation fishing at regional scales for prioritizing management efforts.

Johnson, AF, Moreno-Baez M, Giron-Nava A, Corominas J, Erisman B, Ezcurra E, Aburto-Oropeza O.  2017.  A spatial method to calculate small-scale fisheries effort in data poor scenarios. Plos One. 12   10.1371/journal.pone.0174064   AbstractWebsite

To gauge the collateral impacts of fishing we must know where fishing boats operate and how much they fish. Although small-scale fisheries land approximately the same amount of fish for human consumption as industrial fleets globally, methods of estimating their fishing effort are comparatively poor. We present an accessible, spatial method of calculating the effort of small-scale fisheries based on two simple measures that are available, or at least easily estimated, in even the most data-poor fisheries: the number of boats and the local coastal human population. We illustrate the method using a small-scale fisheries case study from the Gulf of California, Mexico, and show that our measure of Predicted Fishing Effort (PFE), measured as the number of boats operating in a given area per day adjusted by the number of people in local coastal populations, can accurately predict fisheries landings in the Gulf. Comparing our values of PFE to commercial fishery landings throughout the Gulf also indicates that the current number of small-scale fishing boats in the Gulf is approximately double what is required to land theoretical maximum fish biomass. Our method is fishery-type independent and can be used to quantitatively evaluate the efficacy of growth in small-scale fisheries. This new method provides an important first step towards estimating the fishing effort of small-scale fleets globally.

Erisman, B, Heyman W, Kobara S, Ezer T, Pittman S, Aburto-Oropeza O, Nemeth RS.  2017.  Fish spawning aggregations: where well-placed management actions can yield big benefits for fisheries and conservation. Fish and Fisheries. 18:128-144.   10.1111/faf.12132   AbstractWebsite

Marine ecosystem management has traditionally been divided between fisheries management and biodiversity conservation approaches, and the merging of these disparate agendas has proven difficult. Here, we offer a pathway that can unite fishers, scientists, resource managers and conservationists towards a single vision for some areas of the ocean where small investments in management can offer disproportionately large benefits to fisheries and biodiversity conservation. Specifically, we provide a series of evidenced-based arguments that support an urgent need to recognize fish spawning aggregations (FSAs) as a focal point for fisheries management and conservation on a global scale, with a particular emphasis placed on the protection of multispecies FSA sites. We illustrate that these sites serve as productivity hotspots - small areas of the ocean that are dictated by the interactions between physical forces and geomorphology, attract multiple species to reproduce in large numbers and support food web dynamics, ecosystem health and robust fisheries. FSAs are comparable in vulnerability, importance and magnificence to breeding aggregations of seabirds, sea turtles and whales yet they receive insufficient attention and are declining worldwide. Numerous case-studies confirm that protected aggregations do recover to benefit fisheries through increases in fish biomass, catch rates and larval recruitment at fished sites. The small size and spatio-temporal predictability of FSAs allow monitoring, assessment and enforcement to be scaled down while benefits of protection scale up to entire populations. Fishers intuitively understand the linkages between protecting FSAs and healthy fisheries and thus tend to support their protection.

2016
Stewart, JD, Beale CS, Fernando D, Sianipar AB, Burton RS, Semmens BX, Aburto-Oropeza O.  2016.  Spatial ecology and conservation of Manta birostris in the Indo-Pacific. Biological Conservation. 200:178-183.   10.1016/j.biocon.2016.05.016   AbstractWebsite

Information on the movements and population connectivity of the oceanic manta ray (Manta birostris) is scarce. The species has been anecdotally classified as a highly migratory species based on the pelagic habitats it often occupies, and migratory behavior exhibited by similar species. As a result, in the absence of ecological data, population declines in oceanic manta have been addressed primarily with international-scale management and conservation efforts. Using a combination of satellite telemetry, stable isotope and genetic analyses we demonstrate that, contrary to previous assumptions, the species appears to exhibit restricted movements and fine scale population structure. M. birostris tagged at four sites in the Indo-Pacific exhibited no long-range migratory movements and had non-overlapping geographic ranges. Using genetic and isotopic analysis, we demonstrate that the observed movements and population structure persist on multi-year and generational time scales. These data provide the first insights into the long-term movements and population structure of oceanic manta rays, and suggest that bottom-up, local or regional approaches to managing oceanic mantas could prove more effective than existing, international-scale management strategies. This case study highlights the importance of matching the scales at which management and relevant ecological processes occur to facilitate the effective conservation of threatened species. (C) 2016 Elsevier Ltd. All rights reserved.

Ulate, K, Sanchez C, Sanchez-Rodriguez A, Alonso D, Aburto-Oropeza O, Huato-Soberanis L.  2016.  Latitudinal regionalization of epibenthic macroinvertebrate communities on rocky reefs in the Gulf of California. Marine Biology Research. 12:389-401.   10.1080/17451000.2016.1143105   AbstractWebsite

We report on a latitudinal pattern in the structure and species composition of epibenthic macroinvertebrate communities on rocky reefs along a gradient of eight degrees of latitude in the Gulf of California. We provide quantitative evidence of a prominent shift in the taxa dominating these communities, particularly the sessile taxa (Cnidaria, Bivalvia, Annelida, Ascidiacea and Porifera). This pattern was not found in non-sessile taxa (Echinodermata, Decapoda, Cephalopoda, Gastropoda and Polycladida). Based on Bray-Curtis similarity and indicator species analysis we found that the macroinvertebrates of rocky reefs in the Gulf of California are distributed in three broad regions, indicating that sessile taxa are creating such a structure and are related to environmental changes tied to latitude. The northern region (>28 degrees N) was a temperate zone with the coolest water in winter and highest chlorophyll a concentrations, where Octocorallia of the genus Muricea were the dominant taxa. The central region (similar to 24-28 degrees N) had a mix of oceanographic features of the northern and southern regions and was dominated by Echinodermata in terms of species richness and density. The southern region (<24 degrees N) is a subtropical zone with typically warm and clear water, and dominated by Hexacorallia (stony corals). The southern area was less diverse and had lower densities than the central and northern areas. These three communities correspond to known oceanographic discontinuities in the Gulf of California. This implies that future coastal management plans and conservation efforts in the Gulf of California must be regionalized to support their distinct ecological communities.

Ezcurra, P, Ezcurra E, Garcillán PP, Costa MT, Aburto-Oropeza O.  2016.  Coastal landforms and accumulation of mangrove peat increase carbon sequestration and storage. Proceedings of the National Academy of Sciences.   10.1073/pnas.1519774113   Abstract

Given their relatively small area, mangroves and their organic sediments are of disproportionate importance to global carbon sequestration and carbon storage. Peat deposition and preservation allows some mangroves to accrete vertically and keep pace with sea-level rise by growing on their own root remains. In this study we show that mangroves in desert inlets in the coasts of the Baja California have been accumulating root peat for nearly 2,000 y and harbor a belowground carbon content of 900–34,00 Mg C/ha, with an average value of 1,130 (± 128) Mg C/ha, and a belowground carbon accumulation similar to that found under some of the tallest tropical mangroves in the Mexican Pacific coast. The depth–age curve for the mangrove sediments of Baja California indicates that sea level in the peninsula has been rising at a mean rate of 0.70 mm/y (± 0.07) during the last 17 centuries, a value similar to the rates of sea-level rise estimated for the Caribbean during a comparable period. By accreting on their own accumulated peat, these desert mangroves store large amounts of carbon in their sediments. We estimate that mangroves and halophyte scrubs in Mexico’s arid northwest, with less than 1% of the terrestrial area, store in their belowground sediments around 28% of the total belowground carbon pool of the whole region.

Rubio-Cisneros, NT, Aburto-Oropeza O, Ezcurra E.  2016.  Small-scale fisheries of lagoon estuarine complexes in Northwest Mexico. Tropical Conservation Science. 9:78-134. AbstractWebsite

Small-scale fisheries of lagoon-estuarine complexes (LECs) in Northwest Mexico were investigated using official landings data. Species groups found in landings were clustered into three categories according to their life cycle and habitat distribution: Lagoon-estuarine (LE), Transition zone (TZ) and Coastal (CO). Average landings were highest for LE (19,606 t yr(-1)), followed by TZ (7,234 t yr(-1)), and CO (3,155 t yr(-1)). In contrast, the total number of fished species groups had an opposite pattern: LE, TZ, and CO bore 31, 66 and 74 species groups respectively. The number of species groups in LE category significantly increased towards LECs of southern latitudes. The families with highest landings in LECs were Penaeidae, Portunidae, Mugilidae, Scombridae, and Lutjanidae. The area of LECs was significantly correlated with the amount of landings recorded for LE category. A similarity analysis of LECs species groups revealed a latitudinal clustering of northern and southern LECs. Overall, fisheries in LECs produced millions of $US per year, which support socioeconomic activities at the local, regional, and national scale. Although the information and landings data on LECs fisheries in Northwest Mexico have limitations for data analysis, our results suggest that changes in fisheries management of LECs, such as bottom-up management actions where resource users can participate, could help establish more sustainable fishing practices in these ecosystems and allow coastal communities to continue obtaining economic benefits and food supply from LECs in Northwest Mexico.

2015
Erisman, B, Heyman W, Kobara S, Ezer T, Pittman S, Aburto-Oropeza O, Nemeth RS.  2015.  Fish spawning aggregations: where well-placed management actions can yield big benefits for fisheries and conservation. Fish and Fisheries.   10.1111/faf.12132   Abstract

Marine ecosystem management has traditionally been divided between fisheries management and biodiversity conservation approaches, and the merging of these disparate agendas has proven difficult. Here, we offer a pathway that can unite fishers, scientists, resource managers and conservationists towards a single vision for some areas of the ocean where small investments in management can offer disproportionately large benefits to fisheries and biodiversity conservation. Specifically, we provide a series of evidenced-based arguments that support an urgent need to recognize fish spawning aggregations (FSAs) as a focal point for fisheries management and conservation on a global scale, with a particular emphasis placed on the protection of multispecies FSA sites. We illustrate that these sites serve as productivity hotspots – small areas of the ocean that are dictated by the interactions between physical forces and geomorphology, attract multiple species to reproduce in large numbers and support food web dynamics, ecosystem health and robust fisheries. FSAs are comparable in vulnerability, importance and magnificence to breeding aggregations of seabirds, sea turtles and whales yet they receive insufficient attention and are declining worldwide. Numerous case-studies confirm that protected aggregations do recover to benefit fisheries through increases in fish biomass, catch rates and larval recruitment at fished sites. The small size and spatio-temporal predictability of FSAs allow monitoring, assessment and enforcement to be scaled down while benefits of protection scale up to entire populations. Fishers intuitively understand the linkages between protecting FSAs and healthy fisheries and thus tend to support their protection.

Aburto-Oropeza, O, Ezcurra E, Moxley J, Sanchez-Rodriguez A, Mascarenas-Osorio I, Sanchez-Ortiz C, Erisman B, Ricketts T.  2015.  A framework to assess the health of rocky reefs linking geomorphology, community assemblage, and fish biomass. Ecological Indicators. 52:353-361.   10.1016/j.ecolind.2014.12.006   AbstractWebsite

The recovery of historic community assemblages on reefs is a primary objective for the management of marine ecosystems. Working under the overall hypothesis that, as fishing pressure increases, the abundance in upper trophic levels decreases followed by intermediate levels, we develop an index that characterizes the comparative health of rocky reefs. Using underwater visual transects to sample rocky reefs in the Gulf of California, Mexico, we sampled 147 reefs across 1200 km to test this reef health index (IRH). Five-indicators described 88% of the variation among the reefs along this fishing-intensity gradient: the biomass of piscivores and carnivores were positively associated with reef health; while the relative abundances of zooplanktivores, sea stars, and sea urchins, were negatively correlated with degraded reefs health. The average size of commercial macro-invertebrates and the absolute fish biomass increased significantly with increasing values of the IRE. Higher total fish biomass was found on reefs with complex geomorphology compared to reefs with simple geomorphology (r(2) = 0.14, F = 44.05, P<0.0001) and the trophic biomass pyramid also changed, which supports the evidence of the inversion of biomass pyramids along the gradient of reefs' health. Our findings introduce a novel approach to classify the health of rocky reefs under different fishing regimes and therefore resultant community structures. Additionally, our IRH provides insight regarding the potential gains in total fish biomass that may result from the conservation and protection of reefs with more complex geomorphology. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

Leslie, HM, Basurto X, Nenadovic M, Sievanen L, Cavanaugh KC, Cota-Nieto JJ, Erisman BE, Finkbeiner E, Hinojosa-Arango G, Moreno-Baez M, Nagavarapu S, Reddy SMW, Sanchez-Rodriguez A, Siegel K, Ulibarria-Valenzuela JJ, Weaver AH, Aburto-Oropeza O.  2015.  Operationalizing the social-ecological systems framework to assess sustainability. Proceedings of the National Academy of Sciences of the United States of America. 112:5979-5984.   10.1073/pnas.1414640112   AbstractWebsite

Environmental governance is more effective when the scales of ecological processes are well matched with the human institutions charged with managing human-environment interactions. The social-ecological systems (SESs) framework provides guidance on how to assess the social and ecological dimensions that contribute to sustainable resource use and management, but rarely if ever has been operationalized for multiple localities in a spatially explicit, quantitative manner. Here, we use the case of small-scale fisheries in Baja California Sur, Mexico, to identify distinct SES regions and test key aspects of coupled SESs theory. Regions that exhibit greater potential for social-ecological sustainability in one dimension do not necessarily exhibit it in others, highlighting the importance of integrative, coupled system analyses when implementing spatial planning and other ecosystem-based strategies.

Erisman, B, Mascarenas-Osorio I, Lopez-Sagastegui C, Moreno-Baez M, Jimenez-Esquivel V, Aburto-Oropeza O.  2015.  A comparison of fishing activities between two coastal communities within a biosphere reserve in the Upper Gulf of California. Fisheries Research. 164:254-265.   10.1016/j.fishres.2014.12.011   AbstractWebsite

We engaged in collaborative research with two small-scale fishing communities inside the Upper Gulf of California Biosphere Reserve in Mexico, San Felipe (SF) and El Golfo de Santa Clara (GSC), to test how well the geographic heterogeneity of fishing activities within the reserve coincided with current regulations. We compared the two communities in terms of catch composition, fishing effort, ex-vessel prices and revenues, seasonal patterns in fishing activities in relation to the reproductive seasons of target species, and spatial patterns of fishing in relation to managed zones within the reserve. The top four species (Cynoscion othonopterus, Micropogonias megalops, Scomberomorus concolor, Litopenaeus stylirostris) in terms of relative effort, catch, and revenues were the same for both communities but overall fisheries production, effort, and revenues were higher in GSC than SF for these species. Fishing activities in GSC followed a predictable annual cycle that began with L stylirostris and were followed sequentially by the harvesting of C. othonopterus, M. megalops, and S. concolor during their respective spawning seasons, which were associated with seasonal variations in ex-vessel prices. Conversely, catch and revenues in SF were more diversified, less dependent on those four species, less seasonal, and did not show seasonal variations in prices. Interactions between fisheries and managed zones also differed such that SF interacted mainly with the southwest portion of the vaquita (Phocoena sinus) refuge, whereas GSC fished over a larger area and interacted mainly with the northeast portion of the vaquita refuge and the no-take zone. Our results indicate the two communities differ markedly in their socio-economic dependence on fisheries, their spatio-temporal patterns of fishing, their use of and impacts on species, coastal ecosystems and managed areas, and how different regulations may affect livelihoods. Regional management and conservation efforts should account for these differences to ensure the protection of endangered species and to sustain ecosystem services that maintain livelihoods and healthy coastal ecosystems. This study provides further evidence of the ability of collaborative research between scientists and fishers to produce robust and fine-scale fisheries and biological information that improves the collective knowledge and management of small-scale fisheries within marine protected areas. (C) 2014 Elsevier B.V. All rights reserved.

Girón-Nava, A, López-Sagástegui C, Aburto-Oropeza O.  2015.  On the conditions of the 2012 cannonball jellyfish (Stomolophus meleagris) bloom in Golfo de Santa Clara: a fishery opportunity? Fisheries Management and Ecology.   10.1111/fme.12115   Abstract

In 2012, a massive bloom of the cannonball jellyfish Stomolophus meleagris (Agassiz) occurred in El Golfo de Santa Clara (GSC), Sonora, Mexico, allowing the local artisanal fleet to land approximately 20 000 t, which generated almost 3.5 million US$ in revenue (Agencias 2013). Moreover, the bloom generated such enthusiasm that locals invested millions of dollars in infrastructure and equipment hoping that 2013 would bring another successful jellyfish fishing season. The jellyfish never arrived in 2013 and those investments became losses (Organización Editorial Mexicana 2013). This situation prompts the question whether it is possible and responsible to promote fisheries that are based on resources that become available as a result of bloom events. An analysis of environmental conditions that allowed such a massive bloom to occur was undertaken and a brief commentary on the long-term viability of such bloom-related fisheries is presented.

Ramirez-Valdez, A, Aburto-Oropeza O, Palacios-Salgado DS, Correa-Sandoval F, Ramirez-Valdez A, Villasenor-Derbez JC, Cota-Nieto JJ, Hinojosa-Arango G, Reyes-Bonilla H, Dominguez-Guerrero I, Hinojosa-Arango G, Villasenor-Derbez JC, Hernandez A.  2015.  The nearshore fishes of the Cedros Archipelago (north-eastern Pacific) and their biogeographic affinities. California Cooperative Oceanic Fisheries Investigations Reports. 56:143-167. AbstractWebsite

Located in the central region of the west coast of Baja California Peninsula, the Cedros Archipelago consists of five continental islands (Cedros Island, Natividad, San Benito Este, Medio, and Oeste), with Cedros being the largest island in the Mexican Pacific. This archipelago represents the biogeographic transition zone between the temperate and subtropical region and hence, the end of the geographic distribution of a large number of species. Based on field surveys, literature, and scientific collection records, an exhaustive species list of fishes associated with the archipelago and their biogeographic relationships is presented. The checklist includes 269 species belonging to 191 genera, 97 families, 31 orders, and 4 classes. Of the total species, 105 species were recorded in the field, 57 were the result of the literature review, and 218 species of the records were obtained from collections. A total of 14 biogeographic affinities are presented, where 51% of the species have warm-temperate or cold-temperate affinity and 37% have tropical-subtropical affinity. This work highlights the fish diversity present in a transition zone within the temperate and subtropical marine areas of the Northeastern Pacific. More importantly, it reveals a biogeographic region where a great number of species converge, and may be related with the evolutionary history of different taxa and the geological history of the region.

2014
Gomez-Gutierrez, J, Funes-Rodriguez R, Arroyo-Ramirez K, Sanchez-Ortiz CA, Beltran-Castro JR, Hernandez-Trujillo S, Palomares-Garcia R, Aburto-Oropeza O, Ezcurra E.  2014.  Oceanographic mechanisms that possibly explain dominance of neritic-tropical zooplankton species assemblages around the Islas Marias Archipelago, Mexico. Latin American Journal of Aquatic Research. 42:1009-1034.   10.3856/vol42-issue5-fulltext-7   AbstractWebsite

The nearshore zooplankton species assemblage, identified per taxonomic groups (20) and per species for 12 selected groups, was analyzed from samples collected during November 2010 at four volcanic islands of the Islas Marias Archipelago (IMA), located 90-120 km offshore Nayarit, Mexico. From chlorophyll-a concentration and zooplankton biovolume perspective mesotrophic conditions prevailed in comparison with the Gulf of California during November. Crustaceans numerically dominated the zooplankton assemblage (92.3%) [Copepoda (79.2%), Decapoda larvae (4.7%), Cladocera (3.7%), Mysidacea (2.7%), and Euphausiacea (2.0%)]. The other 15 taxonomic groups (7.7% combined) accounted each one less than 1.5% of the relative abundance. Species richness of selected taxa (similar to 56%) included 259 taxa (121 identified to species, 117 to genus, and 21 not identified). Tropical species from neritic affinity clearly dominated zooplankton assemblage around IMA. Five tropical Copepoda species [Calanopia minor (Dana), Clausocalanus jobei Frost & Fleminger, Acrocalanus gibber Giesbrecht, Canthocalanus pauper (Giesbrecht), and Centropages furcatus (Dana)], a cladoceran Pseudevadne tergestina (Claus), and a Mysidacea species (Mysidium reckettsi Harrison & Bowman) dominated the zooplankton assemblage (accounting about 55% of total abundance of the identified species). Except C. furcatus, all these species are not abundant at oceanic regions of the central and northern Gulf of California. The similarity of multiple neritic and tropical species in the zooplankton assemblage from IMA and Cape Corrientes suggests strong coastal-insular plankton connectivity. Episodic current plumes associated with anomalous intense rivers discharge during rainy years, eddies generated by coastal upwelling event that move offshore, and northward regional oceanic circulation are the most likely mesoscale oceanographic processes that cause costal tropical zooplankton drift enhancing coastal-Archipelago species connectivity in this region.

Munguia-Vega, A, Jackson A, Marinone SG, Erisman B, Moreno-Baez M, Giron-Nava A, Pfister T, Aburto-Oropeza O, Torre J.  2014.  Asymmetric connectivity of spawning aggregations of a commercially important marine fish using a multidisciplinary approach. Peerj. 2   10.7717/peerj.511   AbstractWebsite

Understanding patterns of larval dispersal is key in determining whether no-take marine reserves are self-sustaining, what will be protected inside reserves and where the benefits of reserves will be observed. We followed a multidisciplinary approach that merged detailed descriptions of fishing zones and spawning time at 17 sites distributed in the Midriff Island region of the Gulf of California with a biophysical oceanographic model that simulated larval transport at Pelagic Larval Duration (PLD) 14, 21 and 28 days for the most common and targeted predatory reef fish, (leopard grouper Mycteroperca rosacea). We tested the hypothesis that source-sink larval metapopulation dynamics describing the direction and frequency of larval dispersal according to an oceanographic model can help to explain empirical genetic data. We described modeled metapopulation dynamics using graph theory and employed empirical sequence data from a subset of 11 sites at two mitochondrial genes to verify the model predictions based on patterns of genetic diversity within sites and genetic structure between sites. We employed a population graph describing a network of genetic relationships among sites and contrasted it against modeled networks. While our results failed to explain genetic diversity within sites, they confirmed that ocean models summarized via graph and adjacency distances over modeled networks can explain seemingly chaotic patterns of genetic structure between sites. Empirical and modeled networks showed significant similarities in the clustering coefficients of each site and adjacency matrices between sites. Most of the connectivity patterns observed towards downstream sites (Sonora coast) were strictly asymmetric, while those between upstream sites (Baja and the Midriffs) were symmetric. The best-supported gene flow model and analyses of modularity of the modeled networks confirmed a pulse of larvae from the Baja Peninsula, across the Midriff Island region and towards the Sonoran coastline that acts like a larval sink, in agreement with the cyclonic gyre (anti-clockwise) present at the peak of spawning (May-June). Our approach provided a mechanistic explanation of the location of fishing zones: most of the largest areas where fishing takes place seem to be sustained simultaneously by high levels of local retention, contribution of larvae from upstream sites and oceanographic patterns that concentrate larval density from all over the region. The general asymmetry in marine connectivity observed highlights that benefits from reserves are biased towards particular directions, that no-take areas need to be located upstream of targeted fishing zones, and that some fishing localities might not directly benefit from avoiding fishing within reserves located adjacent to their communities. We discuss the implications of marine connectivity for the current network of marine protected areas and no-take zones, and identify ways of improving it.

TinHan, T, Erisman B, Aburto-Oropeza O, Weaver A, Vazquez-Arce D, Lowe CG.  2014.  Residency and seasonal movements in Lutjanus argentiventris and Mycteroperca rosacea at Los Islotes Reserve, Gulf of California. Marine Ecology Progress Series. 501:191-206.   10.3354/meps10711   AbstractWebsite

A detailed understanding of inter- and intraspecific movement patterns is required to understand how marine species interact with surrounding ecological communities, their susceptibility to anthropogenic disturbance (e. g. fishing pressure), or the feasibility of management strategies. Between August 2010 and September 2012, we used acoustic telemetry to continuously monitor movements of 31 Lutjanus argentiventris (yellow snapper) and 25 Mycteroperca rosacea (leopard grouper) at Los Islotes, a small no-take reserve and reported spawning site for both species in the SW Gulf of California. Though the majority of fish from both species exhibited moderate levels of site fidelity to Los Islotes (snapper: present 49 +/- 30% of days since tagging, grouper: 64 +/- 30%), cluster analyses revealed multiple patterns of site fidelity within species. Approximately 30% of snapper exhibited decreases in site fidelity during the spawning season, and snapper did not spawn at the reserve during the study. Grouper spawning aggregations at Los Islotes were visually observed in 2011 and 2012, though the abundance of fish and the intensity of courtship behaviors were reduced in comparison with reported aggregations elsewhere in the Gulf. Three snapper and 2 grouper made repeated movements across pelagic waters between Los Islotes and Marisla Seamount, another documented aggregation site in the SW Gulf. The demonstrated variation in movements of these species over multiple temporal and spatial scales warrants consideration of movement patterns in assessments of reserve performance, as well as the combination of traditional fisheries regulations (e.g. size limits) with marine reserves throughout the Gulf.

Rubio-Cisneros, NT, Aburto-Oropeza O, Murray J, Gonzalez-Abraham CE, Jackson J, Ezcurra E.  2014.  Transnational ecosystem services: The potential of habitat conservation for waterfowl through recreational hunting activities. Human Dimensions of Wildlife. 19:1-16.: Routledge   10.1080/10871209.2013.819536   AbstractWebsite

This article explores transnational ecosystem services in North America, provided by winter habitat for waterfowl in western Mexico coastal lagoons, and the hunting industry supported by these birds in the United States. This article shows that the number of waterfowl harvested in the United States is related to the abundance of waterfowl wintering in Mexico. On average, this flow of ecosystem services annually yields US$ 4.68 million in hunting stamp sales in the western United States. A demand curve, fitted to duck hunting licenses as a function of stamp price and previous-year waterfowl harvest, estimated US$3?6 million in consumer surplus produced in addition to governmental stamp sales revenue. This strongly suggests that waterfowl wintering habitat in western Mexico is economically valuable to U.S. hunters. Because hunters may benefit substantially from these habitats they may be willing to pay for conservation efforts in western Mexico that can result in transnational benefits received in the United States.

2013
Alvarez-Romero, JG, Pressey RL, Ban NC, Torre-Cosio J, Aburto-Oropeza O.  2013.  Marine conservation planning in practice: lessons learned from the Gulf of California. Aquatic Conservation-Marine and Freshwater Ecosystems. 23:483-505.   10.1002/aqc.2334   AbstractWebsite

1. Overfishing, pollution, coastal development and climate change threaten marine biodiversity globally and compromise the services that marine ecosystems provide. Systematic conservation planning (SCP) provides a framework to identify areas where actions can be effective in addressing these threats, while minimizing the costs of interventions. This study investigated the application of SCP in the Gulf of California, a marine hotspot where seven prioritization exercises have been undertaken. 2. The review of planning exercises showed that the use of SCP methods has progressed slowly (gaps include planning for land-sea connections and ecosystem services) and highlighted benefits and difficulties of applying SCP principles and tools. 3. Despite some convergence, important spatial differences were found in priorities between plans. Convergence was evident in well-studied shallow and benthic marine ecosystems. There were also important differences related to the planning approach, methods and extent. Divergence between methodological and spatial similarities between plans suggests that additional factors (e.g. manually delineating priority areas, incorporating updated datasets, random error), in addition to data and objectives, play an important role in defining the distribution of conservation priorities. 4. According to expert opinion, the implementation of new marine protected areas (MPAs) in the region has been influenced by some of the planning exercises. However, uptake of planning outputs has progressed slowly for many reasons (e.g. conflicting mandates and interests between organizations, limited technical capacities and resources, insufficient political commitment). Other benefits of planning included: developing institutional skills and knowledge; improving collaboration and coordination between organizations (including agencies, and local, regional and national NGOs); converging on the need to assess priorities for marine conservation in regional context; and building trust among organizations. 5. The existence of multiple marine conservation plans in the Gulf of California also highlighted some of the complexities and benefits of having multiple sets of priorities.>Copyright (c) 2013 John Wiley & Sons, Ltd.

Reddy, SMW, Wentz A, Aburto-Oropeza O, Maxey M, Nagavarapu S, Leslie HM.  2013.  Evidence of market-driven size-selective fishing and the mediating effects of biological and institutional factors. Ecological Applications. 23:726-741. AbstractWebsite

Market demand is often ignored or assumed to lead uniformly to the decline of resources. Yet little is known about how market demand influences natural resources in particular contexts, or the mediating effects of biological or institutional factors. Here, we investigate this problem by examining the Pacific red snapper (Lutjanus peru) fishery around La Paz, Mexico, where medium or "plate-sized'' fish are sold to restaurants at a premium price. If higher demand for plate-sized fish increases the relative abundance of the smallest (recruit size class) and largest (most fecund) fish, this may be a market mechanism to increase stocks and fishermen's revenues. We tested this hypothesis by estimating the effect of prices on the distribution of catch across size classes using daily records of prices and catch. We linked predictions from this economic choice model to a staged-based model of the fishery to estimate the effects on the stock and revenues from harvest. We found that the supply of plate-sized fish increased by 6%, while the supply of large fish decreased by 4% as a result of a 13% price premium for plate-sized fish. This market-driven size selection increased revenues (14%) but decreased total fish biomass (-3%). However, when market-driven size selection was combined with limited institutional constraints, both fish biomass (28%) and fishermen's revenue (22%) increased. These results show that the direction and magnitude of the effects of market demand on biological populations and human behavior can depend on both biological attributes and institutional constraints. Fisheries management may capitalize on these conditional effects by implementing size-based regulations when economic and institutional incentives will enhance compliance, as in the case we describe here, or by creating compliance enhancing conditions for existing regulations.

Rife, AN, Erisman B, Sanchez A, Aburto-Oropeza O.  2013.  When good intentions are not enough ... Insights on networks of "paper park" marine protected areas. Conservation Letters. 6:200-212.   10.1111/j.1755-263X.2012.00303.x   AbstractWebsite

In efforts to protect the world's oceans, the Convention on Biological Diversity has moved the goal of establishing marine protected areas (MPAs) to cover 10% of the ocean from 2012 to 2020. This adjustment suggests that the rush to establish MPAs without proper resources does not resolve conservation problems. In fact, such actions may create a false sense of protection that camouflages degradation of marine ecosystems on regional scales. To exemplify this phenomenon, we reviewed MPA efficacy in the Gulf of California, Mexico, where some 23,300 km2 have been decreed as MPAs. With the exception of Cabo Pulmo National Park, MPAs have not met conservation or sustainability goals. We examined MPA budgets and foundations' investment in the region and found that funding for management is not the limiting factor in MPA efficacy, although funding for enforcement may be deficient. We conclude that MPAs have failed because of insufficient no-take zones, lack of enforcement, poor governance, and minimal community involvement. We need a new philosophy to implement MPAs to take advantage of the scientific knowledge and monetary investment that have been generated worldwide and ensure that they complement effective fisheries management outside their borders.

Rife, AN, Aburto-Oropeza O, Hastings PA, Erisman B, Ballantyne F, Wielgus J, Sala E, Gerber L.  2013.  Long-term effectiveness of a multi-use marine protected area on reef fish assemblages and fisheries landings. Journal of Environmental Management. 117:276-283.   10.1016/j.jenvman.2012.12.029   AbstractWebsite

The Loreto Bay National Park (LBNP) is a large, multi-use marine protected area in the Gulf of California, Mexico, where several types of small-scale commercial and recreational fishing are allowed, but where less than 1% of the park is totally protected from fishing. The LBNP was created in 1996; its management plan was completed in 2000, but it was not effectively implemented and enforced until 2003. Between 1998 and 2010, we monitored reef fish populations annually at several reefs inside and outside the LBNP to measure the effects of the park on fish assemblages. We also evaluated reported fisheries landings within the LBNP for the same time series. Our results show that reef fish biomass increased significantly after protection at a small no-take site at LBNP relative to the rest of the park. However, the multi-use part of LBNP where fishing is allowed (99% of its surface) has had no measurable effect on reef fish biomass relative to open access sites outside the park boundaries. Reported fisheries landings have decreased within the park while increasing in nearby unprotected areas. Although the current partial protection management regime has not allowed for reef fish populations to recover despite 15 years as a "protected area," we conclude that LBNP's regulations and management have maintained the conditions of the ecosystem that existed when the park was established. These results suggest that community livelihoods have been sustained, but a re-evaluation of the multi-use management strategy, particularly the creation of larger no-take zones and better enforcement, is needed to improve the reef fish populations in the park in order to ensure sustainable fisheries far into the future. These recommendations can be applied to all multi-use MPAs in Mexico where ecosystem recovery is not occurring despite maintenance of fish stocks. (C) 2013 Elsevier Ltd. All rights reserved.

2012
Erisman, B, Aburto-Oropeza O, Gonzalez-Abraham C, Mascarenas-Osorio I, Moreno-Baez M, Hastings PA.  2012.  Spatio-temporal dynamics of a fish spawning aggregation and its fishery in the Gulf of California. Scientific Reports. 2   10.1038/srep00284   AbstractWebsite

We engaged in cooperative research with fishers and stakeholders to characterize the fine-scale, spatio-temporal characteristics of spawning behavior in an aggregating marine fish (Cynoscion othonopterus: Sciaenidae) and coincident activities of its commercial fishery in the Upper Gulf of California. Approximately 1.5-1.8 million fish are harvested annually from spawning aggregations of C. othonopterus during 21-25 days of fishing and within an area of 1,149 km(2) of a biosphere reserve. Spawning and fishing are synchronized on a semi-lunar cycle, with peaks in both occurring 5 to 2 days before the new and full moon, and fishing intensity and catch are highest at the spawning grounds within a no-take reserve. Results of this study demonstrate the benefits of combining GPS data loggers, fisheries data, biological surveys, and cooperative research with fishers to produce spatio-temporally explicit information relevant to the science and management of fish spawning aggregations and the spatial planning of marine reserves.

2011
Erisman, BE, Paredes GA, Plomozo-Lugo T, Cota-Nieto JJ, Hastings PA, Aburto-Oropeza O.  2011.  Spatial structure of commercial marine fisheries in Northwest Mexico. ICES Journal of Marine Science. 68:564-571.   10.1093/icesjms/fsq179   AbstractWebsite

The spatial structure of commercial marine fisheries in Northwest (NW) Mexico was investigated using official landings data from 39 local fisheries offices in the region. Multivariate analyses revealed a clear spatial pattern in fishing activities, in which there was a positive linear relationship between the species composition of fisheries offices and both latitude and longitude. Fisheries offices formed eight distinct clusters organized by similarities in geographic location, species-group composition, and coastal habitat type. Five of the eight clusters comprised offices from the same geographic region and coastal ecosystem, and the other three clusters contained the largest industrial fishing ports in NW Mexico. The results of this study suggest that NW Mexico would benefit from an ecosystem-based management framework that focuses on the direct, spatial connection that exists between coastal habitats, harvested species groups, and fishing activities within each region. Subdivision into five separate regions is proposed, with management attention paid specially to the few industrialized ports whose fishing capacities and geographic ranges of fishing far exceed the other areas.