Shifts in the climate space of temperate cyprinid fishes due to climate change are coupled with altered body sizes and growth rates

Predictions of species responses to climate change often focus on distribution shifts, although responses can also include shifts in body sizes and population demographics. Here, shifts in the distributional ranges (‘climate space’), body sizes (as maximum theoretical body sizes, L∞) and growth rates (as rate at which L∞ is reached, K) were predicted for five fishes of the Cyprinidae family in a temperate region over eight climate change projections. Great Britain was the model area, and the model species were Rutilus rutilus, Leuciscus leuciscus, Squalius cephalus, Gobio gobio and Abramis brama. Ensemble models predicted that the species' climate spaces would shift in all modelled projections, with the most drastic changes occurring under high emissions; all range centroids shifted in a north-westerly direction. Predicted climate space expanded for R. rutilus and A. brama, contracted for S. cephalus, and for L. leuciscus and G. gobio, expanded under low-emission scenarios but contracted under high emissions, suggesting the presence of some climate-distribution thresholds. For R. rutilus, A. brama, S. cephalus and G. gobio, shifts in their climate space were coupled with predicted shifts to significantly smaller maximum body sizes and/or faster growth rates, aligning strongly to aspects of temperature-body size theory. These predicted shifts in L∞ and K had considerable consequences for size-at-age per species, suggesting substantial alterations in population age structures and abundances. Thus, when predicting climate change outcomes for species, outputs that couple shifts in climate space with altered body sizes and growth rates provide considerable insights into the population and community consequences, especially for species that cannot easily track their thermal niches

Morphological features of the bleak Alburnus alburnus (L., 1758) from Międzyodrze

17 meristic and morphometric features were studied in the bleak in the waters of Międzyodrze. Noticeable positive or negative allometry was observed in the growth of head length, horizontal eye diameter, pelvic fins length, body height, and in the distance between pelvic fins and anal fin. In the light of the studied features, the bleak in Międzyodrze places itself in a transitional position between the lake populations and the riverine and estuarine populations

Studies on Psilodraco breviceps Norman,1937 (Pisces, Notothenioidei, Bathydraconidae) from the region of South Georgia

Studies were carried out on morphologic parameters, length-weight relationship, condition, fecundity and food of Psilodraco breviceps - little known benthopelagic fish from the region of South Georgia. Absolute fecundity was within the range 1206-3537. The fish fed mostly on Mysidacea

Studies on growth rate of yellow notothenia, Notothenia gibberifrons Lönnberg, 1905 off South Georgia

The paper demonstrates that scales are not suitable for back readings, due to a poor legibility of their central parts, the peripheral regions being poorly legible in older fish scales as well. One can presume that the scales begin to grow as late as in the second year of life. Most otoliths (sagitta) can be used in back calculations. Based on measurements of radii of various growth zones on the otolith cross-section, mean lengths attained in subsequent years of life were calculated. The von Bertalanffy growth equation parameters were estimated as follows: L∞ = 57.48 cm; K = 1.04; t0 =0.439 yr. The mean length at first maturity was estimated at 37.5 cm, i.e., 65% of L∞

Growth rate of Iceland and North Sea blue whiting, Micromesistius poutassou (Risso,1810), back-calculated from otoliths

The paper presents blue whiting growth rate back-calculated from otolith broken surface radius. The calculations were corrected using the Rosa Lee method

Studies on juvenile Chaenocephalus aceratus (Lönnberg, 1906) (Pisces, Chaenichthyidae) from off South Georgia

Pelagic trawl catches of krill were found to contain 7.8-11.2 cm long (l.t.) juvenile Chaenocephalus aceratus (Lönnberg, l906) whose morphological characters were studied. The following growth rate is hypothesised to take place during the first five years of life: 10, 20, 27, 34, and 40 cm. The fishes studied were found to feed exclusively on krill, dawn and sunset being the times of the most intensive fish feeding activities

Food and feeding behaviour of Parachaenichthys georgianus (Fischer, 1885) and Parachaenichthys charcoti (Vaillant, 1906) (Pisces, Bathydraconidae)

Studies were made on the content of 278 stomachs of Parachaenichthys georgianus from the region of South Georgia and 30 stomachs of Parachaenichthys charcoti from the region of South Shetlands. Small P. georgianus fed mostly on Mysidacea, medium-sized on shrimps and fishes, large specimens on fishes. P. charcoti fed on fishes, Mysidacea and Euphausiacea

Food and feeding behaviour of eel-cod Muraenolepis sp., (Pisces, Gadiformes, Muraenolepididae) from the region of South Georgia

Amphipoda, Cumacea, and Macrura natantia constituted the basic food component of small eel-cod ( 30 cm) consumed fish, Euphausiacea and Macrura natantia. Mean filling index decreased with increasing depth of catches, while percentage of “empty” stomachs increased

The intraspecific geographical variability of horse mackerel Trachurus trachurus (L.) in the West African shelf waters

An attempt to distinguish local stocks of horse mackerel was made basing both on the comparison of morphological features of fish from three West African shelf regions (Ifni: 28°34′-29°52′N, Cap Blanc: 21°00′-24°52′N, Namibia: 22°34′-26°08′S) and on the literature data