Seasonal occurrence and abundance of caridean shrimp larvae at Helgoland, German Bight

Abstract

Plankton samples were collected from January 1985 to January 1986 three times per week at Helgoland to study seasonal occurrence and abundance of caridean shrimp larvae. A total of eleven species were obtained. Ninety-one % of all larvae collected during the sample period belonged to Crangon crangon L. and Crangon allmanni Kinahan, 6 % to Philocheras tn'spinosus Hailstone and3 % to the remaining eight species. Collections were generally dominated by C. placed into three different groups with respect to their seasonal'occurrence. Possible advantages of the timing of larval dispersal relative to predation and food availability are given. The results on seasonal occurrence and relative abundance are discussed in relation to environmental factors (temperature, salinity) as wetl as to the geographical distribution of the species.

Larvae of uncommon caridean decapods in the German Bight: Species composition, distribution and abundance

“…The species composition is in general agreement with species encountered at Helgoland during an intensive one-year plankton samphng programme (Wehrtmann, 1989) (Table 3) ~ Z V" Fig. 11.…”

“…However, larvae of T. cranchii were collected off Helgoland in 1990 and 1991 (Wehrtmann, in prep. ), and adult specimens of P. brevirostn's are relatively common near Helgoland (Wehrtmann, 1989). Furthermore, the distribution of the Palaemonidae clearly demonstrates that developmental stages of this family are confined to estuarine environments, and therefore they cannot be considered to be a regular component of the shrimp larval fauna at Helgoland.…”

“…The aim of the present paper is to describe the distribution and density of developmental stages of shrimps other than Crangonidae in the German Bight during July 1990, after the mildest winter of the century (Beukema, 1992). The results are discussed and compared with the findings of both the continuous plankton records (Rees, 1952(Rees, , 1955Lindley, 1987) and the Helgoland data set (Wehrtmann, 1989;Wehrtmann, in prep.). (July, 1990) 54 ~ N Larvae of uncommon caridean decapods…”

“…Baan et al (1972) reported on the presence of decapod larvae in the southern North Sea, and Wehrtmann (1989) provided detailed information on the seasonal occurrence and abundance of caridean shrimp larvae off Helgoland in the German Bight. Although Wehrtmann (1986) described the presence of shrimp larvae in the extended Elbe estuary, the occurrence and distribution of planktonic stages of non-crangonid species in the German Bight are rather unknown.…”

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

“…At higher temperatures and planktonic food concentration, during late spring and summer (Wiltshire et al 2008), smaller shrimp larvae hatch in the southern North Sea. This match between favorable conditions of food availability and high temperatures with larval peak abundance during spring-summer (Wehrtmann 1989) allows the larvae to exploit rich food resources and reach fast rates of growth and development (Temming and Damm 2002). In this way, our study confirms the hypotheses proposed by Paschke et al (2004) and provides a chemical basis explaining the previously observed seasonal patterns in larval starvation resistance.…”