Mexico Fishery Research Articles

Reproductive biology of the rock oyster Striostrea prismatica in two populations of the Mexican Central Pacific

ABSTRACT The oyster Striostrea prismatica is a fishery-relevant species in the eastern tropical Pacific, particularly in the Mexican Central Pacific (MCP), and little is known about its reproductive cycle. Therefore, our study analysed gametogenesis, sex ratio, sexual maturity stages, shell height at first maturity, and condition index during 2014 and 2015 in El Tizate and La Victoria in the MCP. The sex ratio was significantly biased towards males at both sites, presumably due to ontogeny or fishing pressure. The highest condition index was observed between April and May in both years, while lower values were observed from September to December. The reproductive cycle in both sites was annual, with maturity and spawning from June to August and the degradation phase in August. The condition index showed a negative correlation with temperature and chlorophyll a in both sites: as a result, the period of maximum maturity and spawning coincided with the closure of the fishery in Mexico (June-August). Females had more significant shell height at first maturity than males at both sites, possibly associated with fishing pressure. The information from this study is a significant contribution, but it is necessary to extend the studies to populations further south and further north.

MEXICAN PINK ABALONE (Haliotis corrugata WOOD, 1828) FISHERY MANAGEMENT STRATEGY EVALUATION: A DATA-LIMITED APPROACH

Management procedures (MP) were evaluated to address alternative management of the pink abalone (Haliotis corrugata) fishery in the Mexican Pacific. This assessment utilized the Method Evaluation and Risk Assessment (MERA) platform within the context of management strategy evaluation (MSE). This species has been a crucial component of the abalone fishery in Mexico, with a history dating back to the 19th century. Since 1996, fishery authorities and fishermen have noted a decline in the stock biomass. In response, they implemented various strategies and efforts to address the situation. However, despite these measures, the stock has yet to recover satisfactorily. Eight MP were evaluated, and two corresponded to the status quo (current catch and effort). The simulation results suggest that relying solely on effort-based MP falls short of meeting the management objectives set in the reference points (Biomass and Yield). In contrast, alternative strategies involving different quota allocation strategies (e.g., based on the depletion level) demonstrated superior performance and a higher likelihood of meeting management objectives. Despite incorporating fishery information, the existing management procedures could have performed better in the simulation. Therefore, it is crucial to assess and implement alternative management strategies that are more likely to succeed

Resilience of the governance systems of two MSC certified fisheries in northwestern Mexico

Incentive-based management is an encouraging option in the quest for sustainability, and the Marine Stewardship Council (MSC) is the most prestigious certification standard. It implies sustainability and resilience, but the latter has yet to be explored. Accordingly, we selected two MSC-certified fisheries, the small-scale red lobster fishery (RL) in Baja California (BC) and the small pelagic industrial fishery in Sonora (SP), to prove whether the certification success is reflected in a resilient governance network structure. To do so, we identify structural patterns that drive the resilience of the governance network in two MSC-certified fisheries. Data obtained through stakeholder interviews on different types of stakeholder relationships were used to construct weighted communication matrices to model governance networks. We assessed the individual role of each actor using centrality indices. We also analyzed how stakeholders are integrated into cohesive subgroups of the network. To evaluate resilience, we compared changes in the structure of governance networks by analyzing how network properties change each time the loss of an actor and/or its functionality is simulated. In both fisheries, most of the stakeholders belonged to the productive sector, actors involved in capture, processing, commercialization, and industrialization in the case of SP. For all centrality indices, the most relevant actors were similar or the same in both fisheries and belonged mainly to the regulatory and productive sectors. Cohesive subgroup analysis revealed that both networks are highly connected and collaborative systems. The simulations showed that in both fisheries, the decrease in the number of stakeholders did not cause abrupt changes in the structure of the governance systems. This approach reveals that, even in worst-case scenarios, the tolerance of governance systems to this severe loss of stakeholder diversity is high and suggests that following sustainable certification standards can lead to the promotion of effective and resilient governance networks.

The power of collaboration in multifishery improvement initiatives

Abstract Addressing diverse and complex socio-ecological challenges is crucial for achieving ocean sustainability. This is especially true for effective fishery management, which is vital for the sustainability of marine resources. One way of overcoming barriers to fisheries reform is through interdisciplinary collaboration and innovative management and policy approaches. One such approach is market incentives offered by eco-certification against sustainability standards, such as those set by the Marine Stewardship Council (MSC). Complementary interventions that support sustainability improvements are fishery improvement projects (FIPs) and MSC pathway projects. These interventions have clear intermediary and final objectives, and monitoring impact throughout the implementation process remains important. We interviewed participants of a pathway project from five fisheries in South Africa and Mexico using semistructured interviews designed to capture the nonmonetary impacts of these projects as they progress. Our results show that interventions can play a role in facilitating broader collaboration within a fishery and across stakeholder groups, increasing sustainability awareness. Emphasizing the importance of stakeholder engagement and collaboration, we highlight how the project implementation process can lead to communication changes that lead to improved understanding and collaboration. Importantly, we reflect on the suitability of the survey in monitoring progress in such projects.

Stock assessment and fishing management of green abalone (Haliotis fulgens) along the West Coast of Baja California Sur, Mexico

The green abalone fishery in Mexico has showed declines in the availability of the resource, but the current state of the population is unknown. The aim of this study was to analyze inter-annual variation in recruitment, mortality, total and vulnerable biomass, selectivity, and harvest rate of Haliotis fulgens. A size-structured model was used to assess changes in the population dynamics and management quantities from 2010 to 2019. The model describes the exploitation and growth of individuals in the population, and incorporates a stochastic growth matrix that defines the variation in the length increments of individual to individual. Key results indicated that the recruitment failures occurred in infrequent pulses of varying intensity. Moreover, a slight recovery of total biomass during 2017 (791 t), 2018 (1496 t), and 2019 (1274 t) was observed after a slight increase in recruitment and a decrease in harvest rate. The vulnerable biomass increased 44.38% from 2010 to 2019. The harvest rate revealed that individuals larger than the minimum legal size of 145 mm were under high fishing pressure. The stock assessment model highlights an adverse effect in the population; given the deteriorating conditions of the green abalone fishery, it is imperative to transition fully to a recovery strategy, including all the administrative zones in the assessment and management. The adoption of proactive strategies such as the establishment of reference points, no-fishing reserves, and the implementation of a farming system would facilitate the protection of critical abalone populations, contributing to their medium-term recovery, and would be an economic alternative for local fishers.

Size-Structured Method Applied to the Brown Crab Fishery Callinectes bellicosus in the Gulf of California

The crab fishery of the genus Callinectes is one of the most important fisheries in Mexico. Sonora and Sinaloa are the states on the eastern coast of the Gulf of California, the mainland coast. Sinaloa encompasses the greatest production in Mexico of these species, in particular the Bahía Santa Maria La Reforma (BSMR), supplying the most important catches. A mandatory administrative document for the fishery is the Management Plan of Crab. One of the main weaknesses found in it for Sonora and Sinaloa is the lack of fishery assessment in both states. For this reason, a size-structured method called CASA (Catch-at-Size Analysis) was applied in the BSMR, in the seasons 2000, 2011, and 2014, to C. bellicosus. The first catch size (CW50%) estimated for females was 97.5, 102.5, and 100 mm, while in males, it was estimated at 117.5, 107.5, and 102.5 mm. In the specific case of fishing mortality (F), the algorithm allowed us to find that in the larger sizes, a greater fishing pressure is applied for both females and males, yielding a weighted exploitation rate of 0.047 (2000), 0.119 (2011), and 0.426 (2014) for females and 0.045 (2000), 0.295 (2011), and 0.132 (2014) for males, all below 50% (E = 0.50). The crab C. bellicosus in BSMR is not at risk of overexploitation.

Hermaphroditism and the impact of environmental variables on atresia prevalence in the pen shell Pinna rugosa

The pen shell fishery in northwest Mexico is based on reproductive quota, but the reproductive biology of Pinna rugosa, an economically valuable species, has not yet been documented in its main fishery area. The aim of this study was to evaluate the reproductive cycle of P. rugosa, determine the prevalence of atresia and hermaphroditism, and estimate the effect of environmental variables on its reproduction during 2015. Atresia is part of the reproductive cycle in which the cells undergo degeneration. It generally occurs after spawning to reabsorb compounds but it can also occur from the early stages of gametogenesis, affecting fertilization and recruitment. Gonad samples and environmental parameters were collected monthly from a commercial bank at Laguna Ojo de Liebre (Baja California Sur, Mexico) from January to December 2015. Shell height, sex, gonadal development stages, and atresia prevalence were recorded. The results showed that 14% of the individuals were females, 19% were males, and 67% were hermaphrodites, with 3 forms of functional hermaphroditism. Gonadal inactivity occurred in January, February, November, and December, coinciding with lower temperatures and higher chlorophyll a concentrations. Most individuals spawned in June and July. Calculation of a monthly gonad index revealed that gonad development was positively related to environmental variables (R2 = 0.54). Atresia was observed from March to October and was positively related to environmental conditions (R2 = 0.81). The high prevalence of atresia during periods of high temperature and food scarcity suggests that these environmental parameters can affect the reproductive activity of P. rugosa, and have recruitment and fishery productivity implications.

Estimation of Growth and Size at First Maturity under a Multimodel Approach of Anadara tuberculosa (Sowerby, 1833) on the Southeast Coast of the Gulf of California

The clam fishery in northwestern Mexico encompasses the mangrove cockle Anadara tuberculosa. It is extracted manually, at low tides and between the roots of mangroves. Biological samplings were carried out in Estero Las Lajitas, Sinaloa, from May 2021 to April 2022. A total of 661 A. tuberculosa organisms were analyzed, of which 126 were males, were 363 females and 172 were undifferentiated, yielding a statistically different overall sex ratio between females and males (1♀:0.3♂) (X2 = 113.19; p < 0.05). The length–weight relationship showed a potential type (W = 0.0002L3.125) (95% CI 3.027–3.222 for b). To determine the growth of the species, five models were employed: von Bertalanffy, Gompertz, Logistic, Richards, and Gompertz using an oscillatory component (GO). The Akaike Corrected Information Index for Small Samples (AICC) was used. The GO model yielded the lowest AICC (L∞ = 80.98 mm 95% CI 77.59–84.36, k = 1.02 year−1 95% CI 0.89–1.16), a low growth oscillation intensity (C = 0.03), and slower growth in August (WP = 1.67). The Logistic and Gompertz models were used to calculate the size-at-maturity (L50%). Gompertz obtained the lowest AICC with L50% = 32.53 mm (95% CI 30.67–34.31). Considering the lack of biological information and the parameters generated in the present investigation, as regards A. tuberculosa on the coast of Sinaloa, Mexico, its dissemination is essential for the adequate management of the fishery.

Growth and survival of juvenile red abalone (Haliotis rufescens) fed invasive macroalgae

ABSTRACT Abalone is one of the most important small-scale fisheries in Mexico and is challenged by multiple stressors. For example, the loss of the native main food, Macrocystis pyrifera, and the subsequent takeover of non-indigenous algae species represent a major threat to abalone growth and survival. In Baja California, Mexico two introduced macroalgae, Undaria pinnatifida and Sargassum horneri have become common in the past decade with unknown consequences on native herbivores. In this work, we explored the effect of these invasive algae on the growth and survival of juvenile red abalone, Haliotis rufescens. One hundred and ten juvenile red abalone were tagged and fed with invasive algae U. pinnatifida and S. horneri, and a control with M. pyrifera. Then, the shell length, body weight, and survivorship were assessed monthly for 90 days. Results show that abalone fed U. pinnatifida had a total growth in length, weight, and survivorship, similar to those fed native M. pyrifera. In contrast, abalone fed S. horneri had significantly lower overall performance. Marine heatwaves and other climatic impacts are expected to favour the establishment of invasive species. These results may be relevant to inform local fisheries and management efforts in this area under future scenarios.

Cost Efficiencies of the Shrimp Fishery in Mexico: A Stochastic Frontier Analysis

Fishing sector fuel subsidies are designed to increase profitability by reducing costs. However, despite the number of liters of fuel subsidized in 2018 in Mexico, there is no information available on the effectiveness of the subsidies in reducing cost inefficiencies. The purpose of this study was to estimate the cost efficiency of shrimp fishing companies in Mexico, as well as measure the impact of fuel subsidies on the cost inefficiency of the sector from 2003 to 2018. The True Fixed Effects model was used to represent a Cobb–Douglas stochastic production frontier, which included a shrimp fishing inefficiencies model. The results indicate that shrimp fishing companies could reduce their costs by 25% without reducing their catch levels. Fishing companies in the Gulf of Mexico were more efficient than those operating in the Gulf of California and the South Pacific. Fuel subsidies reduce cost inefficiencies, with a greater effect when the subsidy reaches a level of 20% of the total liters of subsidized fuel.

Regionalization of fish production in Mexico based on production value data in MXN pesos.

Objective: Generate a fishing regionalization activity in Mexico based on the economic criteria due to thevalue of fishery production.Design/Methodology/Approach: Socioeconomic data was taken as well as analyzed from the StatisticalYearbook of Aquaculture and Fisheries of fisheries in Mexico. Subsequently, the findings were organizedin a database with geospatial referent reclassified into nominal or ordinal qualitative statistical values. Thereclassification process was done through the use of a Geographic Information System, specifically withArcview 3.2 software, which allowed the generation of geostatistical analysis procedures through the use ofthe Kriging tool.Results: The results are displayed in a visually referenced database shown on a map constructed by datavectorization. The regionalization map of fisheries in Mexico is based on economic criteria of production valueclassified in four zones with different fishing priority.Limitations/implications: The lack of studies and social, economic and productive indexes of the Mexicanfishery is a limitation in the work of regionalization of fishing activity.Findings/conclusions: The efficiency of the use of Kriging as a multispecific analysis tool can be proven.The proposed regionalization is based solely on the monetary value, an item that has a greater weight inthe decisions made by the institutions, due to its importance in terms of Mexico’s Gross Domestic Product.These criteria together with the use of computational tools allowed the geolocalized regional categorizationof zones with similar characteristics classified into four fishing regions according to their degree of economicimportance: low, medium, high and main.

Bioeconomic analysis of stock rebuilding strategies for the green abalone fishery in Mexico under climate uncertainty

Globally, overexploitation of fishery stocks is a complex problem aggravated by climate change's effects. The green abalone in Mexico is an overexploited fishery, resulting in stakeholders committing to its recovery. Part of a comprehensive co-management strategy was to implement a fishing closure in some fishing areas. Now they are exploring reopening the fishery and gradually increasing fishing efforts. This research evaluates compatible management strategies with stock rebuilding under climate uncertainty. An age-structured bioeconomic model for the green abalone fishery was parameterized, which considered the impact of SST anomalies on population dynamics (i.e., recruitment, mortality, and growth). Three management strategies were evaluated under future climate scenarios (RCP 4.5, RCP 8.5, and a scenario without climate change). Results indicate that an effort level that aims to generate Maximum Sustainable Yield (MSY) based on historical fishery data may lead to overexploitation under warming scenarios. Instead, applying the minimum acceptable effort for the fishing community can support biomass recovery and is a strategy more resilient to climate change. This finding highlights the risk of overexploitation by assuming stock productivity stability under favorable climatic conditions when designing rebuilding plans. A stock rebuilding strategy will be more likely to succeed if it is cautious, recognizes uncertainties, and is flexible in considering stock productivity changes.

True insights or ticking boxes? Rapid assessment of rights‐based management in artisanal fisheries

AbstractRights‐based fisheries management (RBFM) seeks to create market incentives to reduce competition, avoid overexploitation, and increase economic efficiency. Particularly for artisanal fisheries, however, assumptions of RBFM may not be met and its use needs to be carefully considered. This study applies an existing tool (SEASALT) to evaluate the strength of RBFM based on attributes of security, exclusivity, fish mortality, scale, responsibility, limitations, and transferability. Results for 17 fisheries in Mexico show a positive (nonsignificant) relationship between the strength of RBFM and stock status, and no effect on prices or landed value. Real‐world fisheries governance systems are much more complex than the simple linkages between attributes implied in SEASALT, but results highlight pre‐existing monitoring and enforcement capacity as essential for successful RBFM. Transitions to RBFM may strengthen this capacity, but likely cannot create it where it does not already exist. Based on our findings, RBFM strategies may benefit from group quotas with limited transferability to avoid negative social outcomes from consolidation or rent capture by intermediaries; this could potentially build on the latent capacity of traditional community associations common in many artisanal fisheries.

Using a social-ecological systems perspective to identify context specific actions to build resilience in small scale fisheries in Mexico

To promote the resilience and sustainability of coastal social-ecological systems (SES), it is necessary to implement adaptive and participatory management schemes. Successful examples of adaptation to the rapid change in coastal SES exist, but the question of whether these cases may be scalable to other regions and contexts remains. To this end, the present study aimed to identify how successful management strategies implemented in a fishing cooperative in Baja California, Mexico, can be adapted to other coastal SES. In particular, this study aimed to understand whether adaptive co-management of Isla Natividad (IN) could be replicated in Isla Todos Santos (ITS), a biophysically similar coastal SES to IN but with different results with regard to fisheries management. We found that the resource systems and resources in both SESs were similar. However, there were substantial differences with regard to governance and resource users. In Isla Natividad, the level of organization orchestrated by the resource users has contributed to establishing rules and sanctions that have supported the sustainable use of fishery resources. On the contrary, in ITS, the number of resource users and their socioeconomic attributes have impeded the establishment of effective rules or sanctions. The results of this study suggest that the ITS governance system needs to be improved in order to adapt some of the IN management strategies to increase its adaptive capacity. To promote successful adaptive management, it is necessary to develop context-specific adaptive pathways that contribute to greater resilience in the SESs of this region and in other regions that face similar conditions.

Regionalization of the artisan fisheries in Baja California Sur, Mexico using the social criteria of the fishing cooperatives

Objective: To generate a proposal for regional categorization (regionalization) of fishing villages in Baja California Sur, Mexico, following social and economic fishing criteria. Design/Methodology/Approach: Socioeconomic data on fishing in Mexico are analyzed. This regionalization uses data collected in the field on the conditions of artisanal fishing cooperatives in Baja California Sur, Mexico (BCS). Subsequently a geo-referential methodology linked to a database was applied. Database was re-categorized by nominal or ordinal statistical values, as it was the case for each. ArcView 3.2 Geographic Information System (GIS) was used to obtain the geo-referenced classification. Then, a geostatistical analysis derived from the Kriging tool was applied. Results: We obtained a regional classification of fishing in Mexico, displayed in maps with vector data. The regionalization is of a social nature, it shows a classification of cooperation level at artisanal fishing cooperatives in the fishing towns of northern Baja California Sur (BCS). Limitations/Implications: The lack of socioeconomic data on fisheries in Mexico has been an important limitation to generate a more accurate regionalization of the Mexican coasts. Findings/Conclusions: Analyzing the social and organizational factors of fishing is necessary for the understanding of marine socio-ecosystems in Mexico. These criteria joined to the use of computer tools allowed the regional geo-located categorization of areas with similar characteristics. Whit the use of this methodology the efficiency of the use of Kriging as a multi-specific analysis tool can be verified

Rapid vulnerability assessment of Pacific sardine (Sardinops sagax) fisheries facing climate change in Mexico

The Pacific sardine fishery is the most important in terms of catch volume in Mexico. Due to their trophic position, small pelagic fishes respond rapidly and abruptly to ocean climate variability at interannual (ENSO) and decadal time scales (PDO), which is why their response to climate change is expected. The present study applied the Rapid Vulnerability Assessment (RVA) designed for Natural Protected Areas to the context of sardine fishery in northwestern Mexico, expecting that the vulnerability of the fishery to climate change will be the same in the two main fishing areas. The results demonstrate that the RVA is a useful and lissome method, integrating all stakeholders knowledge, including the academic perspective, and serves as an adaptive strategic planning tool upon climate change. Also, because of its dynamics, it was shown to promote co management practices due to the collaborative consensus reached. The sardine fishery from the Gulf of California was considered as the most vulnerable to climate change due to the potential exchange of tropical species of lower commercial value; while environmental changes are expected to favor such fishery in the Pacific along Baja California peninsula. We recommend working on adaptation measures to lower the risk presented by overfishing, and address efforts towards the certification of the fishery in the Pacific region.

Ommastrephid squid paralarvae potential nursery habitat in the tropical-subtropical convergence off Mexico

The Gulf of California and adjacent Pacific have passed through a prolonged warming period that affects the Humboldt squid D. gigas life cycle, which was the third largest fishery in Mexico until its total collapse after 2010. The aims of the present study were (i) to characterize the nursery habitat of paralarvae of the complex Sthenoteuthis oualaniensis–Dosidicus gigas (SD complex) on the basis of 1112 paralarvae collected from zooplankton trawls carried out during ten oceanographic cruises off northwestern Mexico between 2010 and 2017; and (ii) to model the seasonal and interannual variability of the nursery habitat, applying a generalized additive model (GAM) using a regional long-term (1922–2017) hydrographic database. The GAM showed significant relationships of paralarvae abundance with the seasonal average of thermocline depth, absolute salinity, and conservative temperature. The potential nursery habitat of the SD complex paralarvae showed its maximum expected abundance in the entrance of the Gulf of California during spring, when the thermocline depth was shallowest (<30 m). During summer the nursery habitat moved northward along the Pacific west coast of the peninsula. Autumn and winter were less suitable seasons for paralarvae nursery because the thermocline was deep throughout the area of study. Potential nursery habitat did not change interannually in location during La Niña conditions, but did increase the expected abundance in its southern extension. El Niño events contracted the nursery habitat near Cabo San Lucas, and caused the habitat to move northwards over both coasts of the Baja California peninsula. Despite seasonal and interannual climatic variability, two regions remained suitable habitats almost throughout the year. One was associated with coastal upwelling regions (Cabo Corrientes) and the second comprised the oceanic region of high mesoscale kinetic energy located south of Cabo San Lucas. We conclude that the potential nursery habitat of the SD complex is more coastal than oceanic, and is associated with a shallow thermocline in the tropical-subtropical convergence off Mexico. The recent anomalous warming period in this region could drive the changes in the morphology of D. gigas in the Gulf of California, given the effects of environmental variability over early stages of development throughout the adult ontogenesis.

A Framework for Simulating Ecosystem Effects in Data-Poor Small-Scale Fisheries Using Science-Based and Local Ecological Knowledge-Based Models

The constant demand for seafood products and the undeniable effects of fishing on marine ecosystems make it urgent to implement an ecosystem approach, even in data-poor scenarios such as small-scale fisheries. Understanding the impacts of fishing is essential for promoting management strategies that prevent irreversible damage to marine ecosystems. Thus, ecosystem quantitative science-based models have been frequently used to evaluate the effects of fishing, although fishers’ local ecological knowledge (LEK) can aid the implementation of qualitative models, particularly in data-poor conditions. Here, we present a framework for simulating and assessing the effects of fishing following two strategies: (1) for both types of models, we simulated species removal scenarios, and (2) for quantitative science-based models, we fitted time series to dynamically assessed impacts. The impacts were analyzed through ecological indicators commonly used for quantitative models, and because these indicators cannot be easily estimated for qualitative models, we propose the use of topological indicators in both types of models. The approach was applied to three case studies of small-scale finfish fisheries in northwestern Mexico. We found that the ecosystem response to species removal was different in each case study and that the target species can play an important role in ecosystems, but their removal does not generate abrupt changes in the ecosystem structure. The quantitative science-based models were able to reproduce the historical catch trends, which allowed us to reveal that changes in ecosystems are indeed influenced by fishing effort but also by underlying primary productivity. Furthermore, topological and ecological indicators showed similar trends in the quantitative models, which suggests that the former could be useful when data-poor conditions allow only qualitative models. This result confirms the relevance of the participation of fishers in generating qualitative models and their decisive role in the discussion of co-management strategies and risk scenarios in a better-informed manner.

Analysis of sizes and state of ovarian maturity in yellowfin tuna (Thunnus albacares) captured in the Gulf of Mexico

The yellowfin tuna Thunnus albacares is the second most important fishery in Mexico, due to its production costs and commercial value” The species is fished on both coast of the country, with the Pacific Ocean presenting productions lightly higher than that of the Gulf of Mexico where, in spite of the above statement, tuna catches have recently shown a downward trend. For this reason, analysis is required of the size and stage of ovarian maturity and it is necessary to determine whether capture size is the primary reason behind the decline in the yellowfin tuna fishery Three tuna fishing trips were conducted in the Gulf of Mexico in order to gather data pertaining to fork length (Lf) and gonads Histological sections were obtained from the latter for analysis and determination of maturity stage. The results showed that males were predominant (40%) among the individuals for which the sex could be differentiated in the catches of T. albacares. The Lf values in the catch, were between 75 and 162 cm. However, variations in this parameter were found between sexes. The relationship between length and weight showed that the males are larger than the females, however, the equationgiven by the parameters of a=0.9406 and b= 3.4504, demonstrated growth of positive allometric type in both sexes. There was progressive development in the state of ovarian maturity over the months of capture. Chromatin nuclear (CN) was the most frequent phase within primary ovarian development (November, February, March), stages were present, although these did not present a direct relationship to fork length.

An Economic Perspective on Policies to Save the Vaquita: Conservation Actions, Wildlife Trafficking, and the Structure of Incentives

The Upper Gulf of California is a diverse and highly productive ecosystem supporting some of the most important fisheries in Mexico, yet a history of weak fisheries management and illegal fishing threaten the area’s biodiversity and undermine human well-being in the communities along its shores. The vaquita (Phocoena sinus) is endemic to these waters and is on the brink of extinction due to incidental entanglement in gillnets used by small-scale fishers. The resurgence of an illegal gillnet fishery for totoaba (Totoaba macdonaldi), whose swim bladders are highly prized in Hong Kong and continental China, has accelerated the steep decline of the vaquita population. Vaquita is one of a growing number of cases linking illegal wildlife trade, organized crime, and biodiversity decline. This paper provides a summary of key reflections of a panel of fisheries economists gathered at the ninth forum of the North American Association of Fisheries Economists (NAAFE) to evaluate the policies implemented in the Upper Gulf through an economic lens and updated to reflect more recent developments. The panel recognized that poor fisheries management, lack of effective enforcement, distant demand for an illegal product, corruption, and few viable economic alternatives confound efforts to address vaquita bycatch. The complexity of these problems requires a holistic, multidisciplinary approach, combining top-down, direct regulation and bottom-up, participatory and incentive-based instruments. Addressing chronic deficiencies in enforcement, particularly in the very small area where the remaining vaquitas are found, is crucial to prevent imminent extinction. Equally crucial are sustained actions to support legal fishers able to make a good living – with a direct stake in healthy marine ecosystems – as key components of policies to address bycatch and reduce wildlife trafficking. The situation in the Upper Gulf of California is dire, yet similar threats to other marine mammals and wildlife trafficked species may benefit from the experience of the vaquita.