Richard Cudney-Bueno

Rapid effects of marine reserves via larval dispersal.

Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs), with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest.

Establishing a Baseline for Management of the Rock Scallop, Spondylus calcifer (Carpenter 1857): Growth and Reproduction in the Upper Gulf of California, Mexico

Abstract The rock scallop (also known as “donkey thorny oyster,” “spiny oyster,” and “thorny oyster”), Spondylus calcifer, is the largest member of any Panamic Province Spondylus and has played important economic, political, and cultural roles in coastal communities of the Eastern Tropical Pacific for thousands of years. Despite its importance, knowledge of its biology is scant. We assessed seasonal variations in shell and adductor muscle growth, longevity, reproductive age and period, and population sex ratios in the upper Gulf of California, Mexico, the northernmost area within the geographic distribution of this species. Information on shell growth and age was obtained via the use of stable oxygen isotope profiles of shell aragonite cross-referenced with mark recapture data. Spondylus calcifer forms white growth bands during winter and spring months. Shell growth accelerates during warmer months and diminishes during colder months. Likewise, the adductor muscle increases in size and weight during colder months, affecting fishermens distribution of fishing effort. These seasonal variations in growth are likely a result of energetic shifts related to resource allocation pre and post reproduction, which takes place in July-August as water temperatures reach 28°C to 30°C. The species reaches sexual maturity between 2.5–4 y of age and can live to at least 12 y. Overall sex ratios consisted of 1:1 male:female, a population structure in accordance with previous reports for the southern Gulf of California. We discuss our findings in the context of management and conservation of the species.

Modeling responses of coupled social–ecological systems of the Gulf of California to anthropogenic and natural perturbations

Key elements of the rapidly expanding field of ecosystem-based management include: (a) understanding connections among social and ecological systems and (b) developing analytical approaches to inform the necessary trade-offs among ecosystem services and human activities in coastal and marine areas. To address these needs, we investigate the impacts of multiple economic sectors on the marine ecosystem and dependent human community in the Gulf of California with an ecological-economic model. We focus on the spotted rose snapper (Lutjanus guttatus), an economically important species targeted concurrently by the nearshore artisanal fleet, the sportfishing fleet, and by the industrial shrimp fleet as bycatch. Economic returns to the local community are driven by the artisanal fishery catch and the number of tourists who engage in the sportsfishery, and these variables are in turn impacted by fish abundance. We find that the coexistence of the two sectors (and production of both seafood and tourism services) creates stability in key elements of the coupled systems. When the coupled systems are perturbed by changes in exploitation and climate variability, the artisanal fishery responds more rapidly and to a greater degree than the sportsfishery to shifts in the fish population. Our results suggest that vital components of coupled systems may well respond differently to climate variability or other perturbations, and that management strategies should be developed with this in mind. Models like ours can facilitate the development and testing of hypotheses about the form and strength of interactions between ecosystems, services, and the human communities that rely on them.

PANGAS: An Interdisciplinary Ecosystem-Based Research Framework for Small-Scale Fisheries in the Northern Gulf of California

Small-scale fisheries contribute about half of global fish catches, or two-thirds when considering catches destined for direct human consumption (FAO 2014). Small-scale fisheries play an important role in food security and nutrition, poverty alleviation, equitable development, and sustainable use of natural resources, providing nutritious food for local, national, and international markets. More than 90% of the world’s fishers and fish workers (those who work in pre-harvest, harvest, and post-harvest activities, including trade) are employed by small-scale endeavors that underpin local economies in coastal, lakeshore, and riparian ecosystems. This, in turn, generates multiplier economic effects in other sectors (FAO 2014). These activities may be a recurrent sideline undertaking or become especially important in times of financial difficulty. Small-scale fisheries represent a diverse and dynamic sector, often

Isolation and characterization of microsatellite loci in the rock scallop (Spondylus calcifer) (Bivalvia: Spondylidae) from the Northern Gulf California, Mexico

Twelve microsatellite loci were isolated from an enriched genomic library of the rock scallop (Spondylus calcifer). One locus was monomorphic. Overall polymorphic loci, the mean numbers of alleles per locus at one locality was 9.6 (range 3–16), and the average observed and expected heterozygosities were 0.650 and 0.707, respectively. Three loci deviated from Hardy–Weinberg equilibrium, and from these, one locus had and excess of heterozygotes and the other two loci showed deficits of heterozygotes likely due to the presence of null alleles. No evidence of linkage disequilibrium was found among loci. These loci are the first microsatellites ever reported for the monotypic family Spondylidae, and will be useful to validate the predictions of oceanographic larval transport models and connectivity between patchy reefs within fishing areas and marine reserves in the northern Gulf of California, Mexico.

Spondylids of Eastern Pacific Ocean

ABSTRACT Members of the bivalve molluscan family Spondylidae were very important elements in the world view of pre-Hispanic cultures of America, and today remain as symbols of culture heritage in contemporary society. In recent decades, given the importance they have for crafts and jewelry, as well as for fisheries and gastronomy, their exploitation has caused a drastic decrease in natural populations leading to restrictions in fishing. In the present review, data about Spondylus species of eastern Pacific Ocean, describing the symbolism, taxonomy, distribution, biology, and ecology, their status as exploitable resources, the advances in aquaculture of these species, as well as management experiences and conservation efforts are presented.

Isolation and characterization of 13 polymorphic microsatellites for the black murex, Hexaplex nigritus.

Thirteen polymorphic microsatellite markers have been isolated and characterized for the black murex (Hexaplex nigritus). These loci are moderately to highly variable with seven to 37 alleles within 113 individuals from four populations in the Northern Gulf of California. Expected heterozygosities ranged from 0.43 to 0.98. High variability indicates that these markers will be useful for studying population structure and connectivity in this species.

Microsatellite loci for the blue swimming crab (Callinectes bellicosus) (Crustacea: Portunidae) from the Gulf of California, Mexico

Twelve microsatellite markers (six di-nucleotides, four tri-nucleotides and two tetra-nucleotides) were isolated and characterized for Callinectes bellicosus, a commercial crustacean species from the Gulf of California, Mexico. One locus was monomorphic and 11 loci were polymorphic in 32 individual samples from a single location. Overall polymorphic loci, the number of alleles per locus ranged from 2 to 24 (average 10.0), the observed heterozygosity ranged from 0.094 to 0.969 (average 0.603), and the expected heterozygosity varied from 0.089 to 0.935 (average 0.597). One locus deviated significantly from Hardy–Weinberg equilibrium due to an excess of heterozygotes, while another locus showed evidence for the presence of a null allele. No evidence of linkage disequilibrium was found among pair of loci. These markers will be helpful to estimate the level of genetic connectivity over a small spatial and temporal scale in order to identify stocks for the management of this small-scale fishery in the Gulf of California.