Seasonal variations in larval biomass and biochemical composition of brown shrimp, Crangon crangon (Decapoda, Caridea), at hatching

Abstract

The ''brown shrimp'', Crangon crangon (Linnaeus 1758), is a benthic key species in the North Sea ecosystem, supporting an intense commercial fishery. Its reproductive pattern is characterized by a continuous spawning season from mid-winter to early autumn. During this extended period, C. crangon shows significant seasonal variations in egg size and embryonic biomass, which may influence larval quality at hatching. In the present study, we quantified seasonal changes in dry weight (W) and chemical composition (CHN, protein and lipid) of newly hatched larvae of C. crangon. Our data revealed significant variations, with maximum biomass values at the beginning of the hatching season (February-March), a decrease throughout spring (April-May) and a minimum in summer (June-September). While all absolute values of biomass and biochemical constituents per larva showed highly significant differences between months (P \ 0.001), CHN, protein and lipid concentrations (expressed as percentage values of dry weight) showed only marginally significant differences (P \ 0.05). According to generalized additive models (GAM), key variables of embryonic development exerted significant effects on larval condition at hatching: The larval carbon content (C) was positively correlated with embryonic carbon content shortly after egg-laying (r 2 = 0.60; P \ 0.001) and negatively with the average incubation temperature during the period of embryonic development (r 2 = 0.35; P \ 0.001). Additionally, water temperature (r 2 = 0.57; P \ 0.001) and food availability (phytoplankton C; r 2 = 0.39; P \ 0.001) at the time of hatching were negatively correlated with larval C content at hatching. In conclusion, ''winter larvae'' hatching from larger ''winter eggs'' showed higher initial values of biomass compared to ''summer larvae'' originating from smaller ''summer eggs''. This indicates carry-over effects persisting from the embryonic to the larval phase. Since ''winter larvae'' are more likely exposed to poor nutritional conditions, intraspecific variability in larval biomass at hatching is interpreted as part of an adaptive reproductive strategy compensating for strong seasonality in plankton production and transitory periods of larval food limitation.

Reproduction and recruitment of the brown shrimp Crangon crangon in the inner German Bight (North Sea): An interannual study and critical reappraisal

“…The larger eggs reflect an enhanced maternal energy investment to the embryo but do not increase the overall energy demand of the female. The biochemical gross composition does not differ qualitatively but quantitatively between larger and smaller eggs but females produce significantly less large eggs in winter than small eggs in summer (Urzúa & Anger, ). The larger eggs contain more nutrients and enable the early hatching larvae to better cope with poor nutritive conditions in early spring and, particularly, if larvae hatch before the onset of the phytoplankton spring bloom (Urzúa & Anger, ).…”

“…The biochemical gross composition does not differ qualitatively but quantitatively between larger and smaller eggs but females produce significantly less large eggs in winter than small eggs in summer (Urzúa & Anger, ). The larger eggs contain more nutrients and enable the early hatching larvae to better cope with poor nutritive conditions in early spring and, particularly, if larvae hatch before the onset of the phytoplankton spring bloom (Urzúa & Anger, ). Paschke, Gebauer, Buchholz, and Anger () showed significantly higher starvation resistance of larvae hatched from larger eggs compared with those from the smaller eggs.…”

Improvements in larviculture of Crangon crangon as a step towards its commercial aquaculture

“…At later development stages, these differences resulted in asynchronous growth and higher risk of cannibalism (unpublished results). Furthermore, eggs of different females can differ in quality; for instance, environmental conditions during oocyte maturation and embryonic development can have significant influence on larval performance (Urzúa & Anger, ).…”

“…In the case of C. crangon, the lack of broodstock requires researchers to collect berried C. crangon females from the wild throughout the year (Bilgin & Samsun, 2006). (Urzúa & Anger, 2013).…”

Population‐dependent acclimatization capacity of thermal tolerance in larvae of the rocky‐shore barnacle Pollicipes elegans

“…The majority of studies on temperature acclimatization in larvae focus on crustaceans such as shrimp ( Crangon crangon ( Linnaeus 1758), Paschke et al. ; Urzúa & Anger ) and crabs ( Neohelice granulata ( Dana 1851) (as Chasmagnathus granulatus ), Bas et al. ; Halicarcinus planatus ( Fabricius 1775), Diez et al.…”