Summary The present study was carried out to investigate the number of daily feeding sessions that results in maximum growth of juvenile cobia under laboratory conditions. Groups of eight fish (110 g) were randomly distributed in twenty 500‐L tanks and hand‐fed a commercial diet for 60 days. The same amount of feed was offered daily, divided in 1, 2, 3, four or six meals. None of the parameters associated with growth performance (survival, weight gain, specific growth rate, feed intake, condition factor or size variation) showed any significant differences among treatments. Although under the present conditions feeding frequency had no effect on the growth performance of cobia larger than 110 g, in commercial farming operations where large numbers of fish are kept within a single rearing structure, fish may have aggressive interactions during feeding. Under these conditions, it is difficult to ensure that all cobia are fed to satiation and thus it is usual to provide two or more meals per day. The present results indicate that for an individual cobia the provision of more than one daily meal has no significant effect on growth performance.

A shrimp protein hydrolysate (SPH) containing 894.2 g kg À1 crude protein (CP) and 54.3 g kg À1 total lipids was tested as a partial replacement for fish meal (FM) in diets of juvenile cobia. The effects of increasing dietary levels of SPH on the survival, weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), nitrogen retention efficiency (NRE) and daily feed intake (DFI) of cobia with initial body weight of 11.9 g were evaluated. Four isoproteic (from 431.1 to 439.7 g kg À1 ) and isoenergetic (20 825-21 347 MJ kg À1 ) diets were formulated to contain 0 (Control), 120, 240 or 360 g kg À1 of dietary CP derived from SPH. Survival, WG, SGR, FCR, NRE and DFI ranged from 90 to 100%, 40.2-56.5 g, 4.7-6.1% day À1 , 1.04-1.54, 26.3-44.0% and 4.7-6.0% fish À1 day À1 respectively. Survival and DFI were not affected by the dietary treatments. On the other hand, fish fed the control diet and the one containing 120 g kg À1 SPH had higher WG, SGR and FCR. Nitrogen retention efficiency was significantly higher for fish fed diets 0 and 120. It is concluded that up to 120 g kg À1 of SPH in cobia diets can be used with no significant effects on feed utilization and fish performance.

Parasitic isopods of fishes usually show wide distribution and low host specificity. This study investigated the occurrence of gill parasites in 120 specimens of spotted goatfish Pseudupeneus maculatus, marine fish of great economic importance for fishery community. The fish were captured monthly in the Coast of Pernambuco State, Northeast Brazil, between October 2012 and September 2013. Eleven isopods were found and identified as Rocinela signata. We observed lower infections in the gills of P. maculatus (prevalence 8.3%, mean intensity 1.6±0.3 and mean abundance 0.1±0.3) when compared to other studies of different host fishes from geographically close locations. This parasite has been reported from a wide variety of fish species, not only in Brazil, but also in the eastern Atlantic and the Pacific oceans. This is the first report of R. signata in spotted goatfish.

Summary Thie study evaluated the changes in proximate composition and fatty acid profile in the muscle, liver and ovarian tissues of wild‐caught Brazilian mojarra Eugerres brasilianus females during sexual maturation as a starting point for the development of broodstock diets. A total of 114 females captured in the Santa Cruz Canal, Itapissuma, PE, north‐eastern Brazil, from August 2012 to April 2013, were classified into four stages of gonadal development by histological analyses. Ovarian protein and total lipid levels increased with maturation, and a simultaneous decrease in liver protein and lipid levels was observed. The levels of arachidonic acid (ARA, 20:4n‐6), eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA, 22:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) also increased in the ovary as the gonadal development proceeded; they represented 96.4% of the total highly unsaturated fatty acids (HUFA) in the ovaries of fully mature females. These findings highlight the need to include protein and lipid‐rich sources containing n‐6 HUFA, particularly ARA, and n‐3 HUFA (EPA, DPA and DHA) in the diets of Brazilian mojarra breeders.