Latitudinal changes in the lipid content and fatty acid profiles of juvenile female red squat lobsters (Pleuroncodes monodon) in breeding areas of the Humboldt Current System

Abstract

The red squat lobster Pleuroncodes monodon is a species of high commercial value that inhabits the Humboldt Current System. Along the Chilean coast, two populations are exploited by the fishing industry, one located off the coast of Coquimbo and the other off the coast of Concepción. Yet, it is unknown whether there are differences in the “bioenergetic fuel” (measured as lipid content and fatty acid profile) of juvenile populations of these two fishing units and whether these bioenergetic compounds can be modulated by differences in the environmental parameters (such as temperature or chlorophyll-a) of their breeding areas. To shed some light on this, we measured the lipid content and fatty acid profiles of the viscera and muscle of juvenile female red squat lobsters from these two fishing units, specifically from breeding areas near long-exploited fishing grounds: a) the northern fishing unit (NFU, from 26°S to 30°S) and b) the southern fishing unit (SFU, from 32°S to 37°S). We found differences in the lipid content, fatty acid profiles, and ratios of saturated fatty acids (C16:0/C18:0) of juvenile females from these two locations. In addition, the essential fatty acids (DHA/EPA) found in the viscera versus the muscle of these lobsters varied significantly. Juvenile females from the SFU (i.e. Concepción) showed a higher lipid content compared to the juvenile females from the NFU (i.e. Coquimbo). Consistently, individuals from the SFU had a higher content of fatty acids, which also proved to be richer in saturated and monounsaturated fatty acids compared to those from the NFU. Our results are important for the fisheries in both areas because these juvenile populations are the source of new recruits for the adult populations that are exploited by the fishing industry. Our study also aids in determining which populations are healthier or of better quality in bioenergetic terms. Furthermore, increasing the incorporation of bioenergetic parameters in fishery models is essential for the recruitment and stock assessment within an ecosystem approach, since it allows for the evaluation of the nutritional condition of different fishing populations.

Inter‐sexual comparison of body biomass, proximate biochemical composition, and fatty acid profiles of new juvenile squat lobsters (Pleuroncodes monodon) in the Southeast Pacific Ocean

“…In the HCS, an important nursery area of P. monodon has been recognized off the southern coast of Chile (Guzmán-Rivas et al, 2021;Roa & Tapia, 1998). Herein, the new juvenile squat lobsters are directly recruited into the adult squat lobster population, which is exploited by industrial fisheries (Roa & Tapia, 1998;SUBPESCA, 2019).…”

“…The new juvenile squat lobsters from this nursery area are directly recruited into the adult red squat lobster population, which is exploited by industrial fisheries (Guzmán-Rivas et al, 2021). Despite the importance of new juvenile P. monodon for recruitment estimations in fishery management models (Zilleruelo et al, 2020), their nutritional status at the onset of their benthic phase remains unknown.…”

Contrasting nursery habitats promote variations in the bioenergetic condition of juvenile female red squat lobsters (Pleuroncodes monodon) of the Southern Pacific Ocean

“…At lower latitudes, warmer waters have proven to lack marked seasonality of biological productivity, while at higher latitudes colder waters have registered a marked seasonality of productivity ( Escribano, Fernández & Aranís, 2003 ; Montecino & Lange, 2009 ; Thiel et al, 2007 ). These differences in environmental conditions across a latitudinal gradient have a direct impact on the physiological traits of early life stages of many marine species that support important fishing activities in the HCS ( Fischer & Thatje, 2016 ; Fischer et al, 2009 ; Guzmán-Rivas et al, 2021a ).…”

“…Also, the lipid/protein ratio is important as in marine animals it indicates the state of health and/or nutritional quality of individuals and allows to discern the metabolic substrate as a source of available energy (lipid form) for fundamental physiological processes (survival, growth, and reproduction) ( Aliyu-Paiko, Hashim & Shu-Chien, 2010 ). Understanding the variations in morphometric and biochemical parameters of juveniles at a large spatial scale throughout the HCS could thus have significant implications for the management and conservation strategies of this fishery resource by helping to identify sources of recruitment and/or nursery grounds ( Brosset et al, 2021 ; Guzmán-Rivas et al, 2021a ). Considering that these parameters could also aid in tracing marine resources back to their geographic origins, they could assist in the identification of populations with superior energetic conditions (regarding the traceability concept, see: ( Leal et al, 2015 ; Ricardo et al, 2017 ; Ricardo et al, 2015 )), which should be targeted in the future exploitation of fisheries ( FAO, 2019 ; Olsen & Borit, 2013 ).…”

“…These females will produce the offspring that recruit to adult populations ( Hamasaki & Kitada, 2008 ) and maintain the fishing stock (for details on the concept of “’source’ & ’sink”’ in population dynamics of marine crustaceans, see: ( Hansen, 2011 ; Lipcius et al, 1998 ). In an ecological context, a recent study indicated that the fatty acid profile of P. monodon juveniles may vary according to their geographic origin and/or breeding areas throughout the HCS ( Guzmán-Rivas et al, 2021a ), and that these variations could directly influence the nutritional and/or bioenergetic condition of individuals. This study also highlighted the fact that to help predict the “bioenergetic condition” of subsequent exploitable populations, future research must analyze other key parameters of juvenile individuals, including body mass ( e.g.…”