Seasonal cycles of reserves in relation to reproduction in Sebastes

Abstract

SynopsisSeasonal cycles of reserve deposition and utilization in many fishes, amphibians and reptiles alleviate temporal mismatches of energy supply and demand. Utilization of reserves can be related to maintenance during periods of reduced food supply, to reproduction, particularly during periods of poor food availability, and to migration. Published data on the seasonal cycles of reserves and reproduction in Sebastes suggest that reserves are important for maintenance during wintertime periods of low food availability. Unlike many other ectothermic vertebrates, some species of Sebastes deposit fat reserves at the same time as gametogenesis, a pattern consistent with the longevity and iteroparity evident in the genus. Other species of Sebastes have similar seasonal timing of fat cycles, but since reproduction takes place later in the year, the decline in reserves during winter coincides with the main period of reproductive activity. The significance of this is not clear. Interspecific differences in amounts of reserves may be related to geographical differences in the seasonality or abundance of food. Intraspecific variation in reserves, marked most strongly by allometry of reserves with regard to fish length, bears further study, since it may link the proces of sexual maturation and the responses of repeat spawners to variability in food supply and other environmental factors. IntroductionIn many animals some assimilated food is allocated to reserves rather than to immediate use, in what is generally seen as a means of ameliorating temporal mismatches between food supply and energy demand (Love 1970, Shul'man 1974, Derickson 1976b, King & Murphy 1985. The particular proximate function of reserves is often indicated by the timing of reserve deposition and utilization in relation to temporal changes in environmental factors and physiological demands. Knowledge of that function can contribute to an understanding of the important factors in the relationship of an organism to its environment. The deposition and use of reserves are also important in the overall allocation of energy in an organism and thus have an ultimate function in its demography and life history. In the latter regard, costs of reserve deposition, in terms of other immediate uses to which the energy could have been applied (Slobodkin 1962, Calow 1977, are balanced against the benefits of reserve utilization, and the trade-offs are evaluated in the context of the allocation of resources to current versus future reproduction (Fisher 1958).The purpose of this paper is to describe ways that knowledge of the patterns of reserve deposition and utilization can contribute to our understanding of the ecology and life history of Sebastes. To that end, I will present some background on the functions of reserves in ectothermic vertebrates, including complications in the interpretation of these 58 functions, and then discuss past and potential future work on the role of reserves in the ecology and life history of Sebastes species. Functions of reserves in ectot...

Geometric morphometric analysis of cyclical body shape changes in color pattern variants of Cichla temensis Humboldt, 1821 (Perciformes: Cichlidae) demonstrates reproductive energy allocation

“…Although the liver is recognized as an important site of lipid deposition and reserve storage in fishes (Larson, 1991;Helfman et al, 1997), data analyzed during this study pointed to a dichotomy between reserves used for gametogenesis and for maintenance, justifying further analysis of the phenomenon. This study initially focused on the effect of corporal fatty reserve deposition (in the muscles, mesentery and fin bases) in specimens without direct consideration of liver reserves for several reasons; first, the geometric morphometric analysis in this study was based on the use of uniformly positioned photographs acting as specimens.…”

“…Second, although patterns of reserve deposition (specifically regarding liver reserve versus alternate corporal reserve deposition) vary with species and life history parameters, the literature shows that fishes whose reproductive period does not coincide precisely with periods of low food availability or high energy requirements may have offset periods of reserve deposition and consumption between the liver and corporal deposits. When reproductive maturation is disengaged from migration, maintenance or periods of minimal food availability, increases in hepatosomatic index (HSI) are not necessarily synchronized with increases in corporal reserve deposition or utilization (Larson, 1991;Schaan et al, 2009). Further it is suggested that materials essential to gametogenesis are stored in the liver (Craig et al, 2000;Regost et al, 2001) and that body fat is not metabolically essential for reproduction; rather it is used primarily for maintenance during low food or high energy consumption periods, such as winter in temperate zone fishes (Larson, 1991).…”

“…When reproductive maturation is disengaged from migration, maintenance or periods of minimal food availability, increases in hepatosomatic index (HSI) are not necessarily synchronized with increases in corporal reserve deposition or utilization (Larson, 1991;Schaan et al, 2009). Further it is suggested that materials essential to gametogenesis are stored in the liver (Craig et al, 2000;Regost et al, 2001) and that body fat is not metabolically essential for reproduction; rather it is used primarily for maintenance during low food or high energy consumption periods, such as winter in temperate zone fishes (Larson, 1991). This may be the case in C. temensis during fry guarding.…”

CONTENIDO DE GRASA Y PROTEINA EN Pygocentrus cariba, Prochilodus mariae, Plagioscion squamosissimus, Piaractus brachypomus e Hypostomus plecostomus EN UNA LAGUNA DE INUNDACION DEL ORINOCO MEDIO

“…Específicamente los contenidos de grasa y proteína están estrechamente relacionados con la alimentación, la migración y los cambios sexuales asociados con el desove, como consecuencia de los períodos de inanición que frecuentemente presentan. La migración y el desove generalmente ocasionan un gasto de la energía que tienen los peces almacenada en forma de grasa mientras que aquellas especies que realizan largas migraciones, también pueden utilizar las reservas de proteína, además de las reservas de grasa, como fuente de energía [4,6,17,20].…”

“…Específicamente los contenidos de grasa y proteína están estrechamente relacionados con la alimentación, la migración y los cambios sexuales asociados con el desove, como consecuencia de los períodos de inanición que frecuentemente presentan. La migración y el desove generalmente ocasionan un gasto de la energía que tienen los peces almacenada en forma de grasa mientras que aquellas especies que realizan largas migraciones, también pueden utilizar las reservas de proteína, además de las reservas de grasa, como fuente de energía [4,6,17,20].Después de la migración y el desove, los peces recuperan el contenido de proteína a través del alimento consumido, a la vez que aumentan notablemente el contenido de grasa [31]. Este parámetro es el que muestra generalmente una mayor variación anual con relación al contenido de proteína, con una curva estacional característica que frecuentemente presenta un mínimo cuando se acerca la época del desove.…”