Growth and food consumption of whiting Merlangius merlangus

Abstract

In the western Baltic Sea (WBS), whiting Merlangius merlangus is the main piscivorous fish together with cod Gadus morhua. In the present study, we investigate the growth and food consumption rates of WBS M. merlangus and compare the growth rates of males and females with those of M. merlangus in the North Sea (NS). Food consumption rates are estimated directly from sampled stomach contents in the WBS using a gastric evacuation rate model and indirectly by using a static energy-budget model together with the growth rates. The results indicate that male and female M. merlangus in the WBS have similar feeding and growth strategies, while in the NS M. merlangus show more pronounced differences in food consumption and growth dynamics between the sexes. Female WBS M. merlangus grow significantly slower than their conspecifics in the NS, but there is no significant difference for males. Sexual size dimorphism is seen in both areas, but for M. merlangus in the WBS the difference is less pronounced. Food consumption rates in the WBS differ between seasons, with the lowest food intake in the first 2 quarters of the year and the highest in the 3rd quarter. No differences in consumption rates were seen between males and females, which could be related to the more similar growth pattern seen for M. merlangus in the WBS.

Parameterizing an expanded square root model to account for the effects of temperature, meal size, and body size on gastric evacuation rate in farmed brown trout

“…GER derived from laboratory experiments, coupled with field‐based data, has been used to quantify predatory fishes’ impacts upon prey populations (Andersen et al, 2017; Bajkov, 1935; Mychek‐Londer & Bunnell, 2013; Casini et al, 2020; Ross et al, 2018; Seyhan & Grove, 1998). Several predictor variables in GER modelling including temperature, fish size, meal size, and dietary energy density have been found to influence GER in fish (Andersen, 2012; Das et al, 2018; Jobling et al, 1977; Mazumder et al, 2020; Yokoyama et al, 2020).…”

Food Composition of the Whiting, Merlangius merlangus in the South-eastern Coast of the Black Sea

“…Another study reported that 50% of the stomachs examined were empty in all seasons and approximately 20% were completely full in all seasons in Rize offshore of the South-eastern Black Sea in 2004-2005(Mazlum ve Bilgin, 2014. In the western Baltic Sea, the rate of empty stomachs was determined as 34% by Ross et al (2018). According to that study, the rate of empty stomachs was high, possibly because whiting followed a different feeding strategy or it was fed less but larger foods.…”

“…According to Hislop et al (1991), whiting is one of the most important carnivorous fish species in the North Sea. Ross et al (2018) report that this species is the main piscivorous species in the western Baltic Sea. As stated by many authors above, the whiting is a carnivorous species.…”

Golden apple snail (Pomacea canaliculata) as an alternative protein source in Pasupati catfish (Pangasius sp.) fish feed

“…In addition, vitamin was also added and tapioca was used as binder. The need for balanced nutrition in fish feed will vary according to fish age and size, environmental conditions, reproduction, and physiological activity (Ross et al 2018).…”