Destructive fishing : an expert‐driven definition and exploration of this quasi‐concept

Numerous policy and international frameworks consider that “destructive fishing” hampers efforts to reach sustainability goals. Though ubiquitous, “destructive fishing” is undefined and therefore currently immeasurable. Here we propose a definition developed through expert consultation: “Destructive fishing is any fishing practice that causes irrecoverable habitat degradation, or which causes significant adverse environmental impacts, results in long-term declines in target or nontarget species beyond biologically safe limits and has negative livelihood impacts.” We show strong stakeholder support for a definition, consensus on many biological and ecological dimensions, and no clustering of respondents from different sectors. Our consensus definition is a significant step toward defining sustainable fisheries goals and will help interpret and implement global political commitments which utilize the term “destructive fishing.” Our definition and results will help reinforce the Food and Agricultural Organization's Code of Conduct and meaningfully support member countries to prohibit destructive fishing practices

Análisis funcional de la red trófica de Bahía Magdalena Baja California Sur, México

El objetivo del presente estudio fue desarrollar un modelo trófico (ECOPATH con ECOSIM) para caracterizar la estructura y función de la trama alimentaria de Bahía Magdalena. El modelo consta de 24 grupos funcionales, siendo dominado por grupos de niveles tróficos secundarios y terciarios, que generan un tercio de los flujos de biomasa total. Los flujos totales del sistema y la eficiencia de transferencia promedio entre niveles tróficos, encajan bien en el rango reportado para otros ecosistemas costeros tropicales del mundo. Una fracción alta de los flujos totales se destina para el mantenimiento de la estructura de la red trófica. El índice de conectancia (IC) fue igual a 0,2, esto significa que sólo hay 20% de las conexiones totales posibles en la trama alimentaria. Una jerarquización de los diversos componentes del sistema en términos de su contribución a la función del sistema reveló que los productores primarios bentónicos y los detritos contribuyen 53% al total de la ascendencia. La idea de un control de la energía de arriba hacia abajo (a través de los principales depredadores) es consistente con otros hallazgos, dicho resultado sugiere que las especies de nivel trófico superior afectan negativamente a otros componentes del ecosistema. Se sugiere emplear el modelo en el corto plazo, para realizar aproximaciones exploratorias que pongan a prueba hipótesis relacionadas con los mecanismos bióticos y abióticos que ocasionen cambios en la estructura y función de la red trófica a través del tiempo, y por tanto contribuyan a entender como la estructura de la trama trófica puede contribuir a la resiliencia de las comunidades biológicas marinas

Age and residency duration of loggerhead turtles at a North Pacific bycatch hotspot using skeletochronology.

For migratory marine animals, like sea turtles, effective conservation can be challenging because key demographic information such as duration of life stages and exposure to spatially explicit threats in different habitats are often unknown. In the eastern Pacific near the Baja California Peninsula (BCP), Mexico, tens of thousands of endangered North Pacific loggerhead sea turtles (Caretta caretta) concentrate at a foraging area known to have high rates of fishery bycatch. Because stage survivorship of loggerheads in the BCP will vary significantly depending on the number of years spent in this region, we applied skeletochronology to empirically estimate residency duration in this loggerhead hotspot. The observed age distribution obtained from skeletochronology analysis of 146 dead-stranded loggerheads ranged from three to 24 years old, suggesting a BCP residency of >20 years. Given the maximum estimated age and a one-year migration to western Pacific nesting beaches, we infer age-at-maturation for BCP loggerheads at ~25 years old. We also examine survivorship at varying BCP residency durations by applying our findings to current annual mortality estimates. Predicted survivorship of loggerheads spending over 20 years in this BCP foraging habitat is less than 10%, and given that ~43,000 loggerhead turtles forage here, a significant number of turtles are at extreme risk in this region. This is the first empirical evidence supporting estimated age-at-maturation for BCP North Pacific loggerheads, and the first estimates of BCP stage survivorship. Our findings emphasize the urgent need for continued and effective international conservation efforts to minimize bycatch of this endangered species

Age and residency duration of loggerhead turtles at a North Pacific bycatch hotspot using skeletochronology.

For migratory marine animals, like sea turtles, effective conservation can be challenging because key demographic information such as duration of life stages and exposure to spatially explicit threats in different habitats are often unknown. In the eastern Pacific near the Baja California Peninsula (BCP), Mexico, tens of thousands of endangered North Pacific loggerhead sea turtles (Caretta caretta) concentrate at a foraging area known to have high rates of fishery bycatch. Because stage survivorship of loggerheads in the BCP will vary significantly depending on the number of years spent in this region, we applied skeletochronology to empirically estimate residency duration in this loggerhead hotspot. The observed age distribution obtained from skeletochronology analysis of 146 dead-stranded loggerheads ranged from three to 24 years old, suggesting a BCP residency of >20 years. Given the maximum estimated age and a one-year migration to western Pacific nesting beaches, we infer age-at-maturation for BCP loggerheads at ~25 years old. We also examine survivorship at varying BCP residency durations by applying our findings to current annual mortality estimates. Predicted survivorship of loggerheads spending over 20 years in this BCP foraging habitat is less than 10%, and given that ~43,000 loggerhead turtles forage here, a significant number of turtles are at extreme risk in this region. This is the first empirical evidence supporting estimated age-at-maturation for BCP North Pacific loggerheads, and the first estimates of BCP stage survivorship. Our findings emphasize the urgent need for continued and effective international conservation efforts to minimize bycatch of this endangered species

Marine turtle regional management units 2.0:an updated framework for conservation and research of wide-ranging megafauna species

Delineating spatial boundaries that accurately encompass complex, often cryptic, life histories of highly migratory marine megafauna can be a significant conservation challenge. For example, marine turtles range across vast ocean basins and coastal areas, thus complicating the evaluation of relative impacts of multiple overlapping threats and the creation of coherent conservation strategies. To address these challenges, spatially explicit ‘regional management units’ (RMUs) were developed in 2010 for all marine turtle species, globally. RMUs were intended to provide a consistent framework that organizes conspecific assemblages into units above the level of nesting rookeries and genetic stocks, but below the species level, within regional entities that may share demographic trajectories because they experience similar environmental conditions and other factors. From their initial conception, RMUs were intended to be periodically revised using new information about marine turtle distributions, life history, habitat use patterns, and population structure. Here, we describe the process used to update the 2010 RMU framework by incorporating newly published information and inputs from global marine turtle experts who are members of the IUCN Marine Turtle Specialist Group. A total of 48 RMUs for 6 of 7 marine turtle species and 166 distinct genetic stocks for all 7 species are presented herein. The updated RMU framework reflects a significant advance in knowledge of marine turtle biology and biogeo - graphy, and it provides improved clarity about the RMU concept and its potential applications. All RMU products have been made open access to support research and conservation initiatives worldwide.</p

Destructive fishing:An expert-driven definition and exploration of this quasi-concept

Numerous policy and international frameworks consider that “destructive fishing” hampers efforts to reach sustainability goals. Though ubiquitous, “destructive fishing” is undefined and therefore currently immeasurable. Here we propose a definition developed through expert consultation: “Destructive fishing is any fishing practice that causes irrecoverable habitat degradation, or which causes significant adverse environmental impacts, results in long-term declines in target or nontarget species beyond biologically safe limits and has negative livelihood impacts.” We show strong stakeholder support for a definition, consensus on many biological and ecological dimensions, and no clustering of respondents from different sectors. Our consensus definition is a significant step toward defining sustainable fisheries goals and will help interpret and implement global political commitments which utilize the term “destructive fishing.” Our definition and results will help reinforce the Food and Agricultural Organization's Code of Conduct and meaningfully support member countries to prohibit destructive fishing practices.</p

Destructive Fishing: an expert-driven definition and exploration of this quasi-concept

Numerous policy and international frameworks consider that ‘destructive fishing’ hampers efforts to reach sustainability goals. Though ubiquitous, ‘destructive fishing’ is undefined and therefore currently immeasurable. Here we propose a definition developed through expert consultation: “Destructive fishing is any fishing practice that causes irrecoverable habitat degradation, or which causes significant adverse environmental impacts, results in long-term declines in target or non-target species beyond biologically safe limits and has negative livelihood impacts.” We show strong stakeholder support for a definition, consensus on many biological and ecological dimensions, and no clustering of respondents from different sectors. Our consensus definition is a significant step towards defining sustainable fisheries goals and will help interpret and implement global political commitments which utilise the term 'destructive fishing'. Our definition and results will help reinforce the FAO Code of Conduct and meaningfully support member countries to prohibit destructive fishing practices