Sardine early survival, physical condition and stress after introduction to captivity

Abstract

The main factors that affect early survival, physical damage and stress reactions of sardine Sardina pilchardus after live capture and introduction to captivity were examined. A total of 2800 sardines were captured alive from commercial purse seiners in five trials off southern Portugal and monitored for 4 weeks in aquaculture tanks. Survival rates varied considerably between trials (from <20 to >80% after a month), with most deaths occurring in the first 5 days. Sardine early survival was affected by factors related to conditions at sea (catch composition, sea temperature and transportation density), during introduction to captivity (magnitude of thermal shock, land transportation duration and use of antibacterial treatment) and, possibly, their interaction. Physical damage was related to the probability of dying, with fish that died during the first week showing significantly higher scale loss and larger caudal fin erosion that those that were alive in the same period. For all stress variables measured (blood haematocrit, cortisol, glucose and ions in the plasma), the most extreme values were attained during introduction to captivity or in the first hours after. After 2 weeks in captivity, most variables had returned to levels close to those observed at the onset of purse-seine fishing, suggesting that maintenance conditions were adequate to permit a rapid recovery from fishing and transport stress.

Culture viability of <em>Sardina pilchardus</em> (Fish, Teleost): Preliminary results of growth in captivity up to 18 months

“…Miranda et al (1992), Silva and Miranda (1992) and Marcalo et al (2008) also reported very low survival during the first feeding experiments on sardine larvae.…”

“…Laboratory experiments using wild sardine specimens have dealt with acclimation to captive conditions (Marcalo et al 2008), induction to spawning (Olmedo et al 1990), embryonic development (Miranda et al 1990) and larval rearing (Blaxter 1969, Silva and Miranda 1992. Garrido et al (2007Garrido et al ( , 2008 described both the feeding behaviour of sardines under culture conditions, and the diet and food intensity in the wild.…”

Evaluation of the physiological status of the Pacific sardine, Sardinops sagax caeruleus, acclimated to different thermal regimes based on selected blood parameters

“…However, there are a limited number of studies assessing the response of blood parameters of marine pelagic and schooling species to stressful conditions. For instance, Marçalo et al (2006Marçalo et al ( , 2008 found that the European sardine (Sardina pilchardus) exhibited increasing cortisol and glucose levels after being exposed to purse seine fishing and captivity.…”

Understanding social sustainability of capture fisheries

“…Higher density in the net could also explain the higher mortality of herring and South American pilchard after purse seining and net burst (Misund and Beltestad, 1995) or slipping (Mitchell et al, 2002) rather than after purse seining alone, likely due to the high density in the net prior to net burst or slipping. With regard to species composition in the net, mortality of sardine was lower when only sardine were caught than when other species were caught as well (Marçalo et al, 2008).…”

“…A larger change in water temperature resulted in higher mortality of sardine (Marçalo et al, 2010(Marçalo et al, , 2008. Longer fishing duration resulted in higher mortality of chinook salmon (Candy et al, 1996), mackerel (Lockwood et al, 1983), sardine (Marçalo et al, 2010) and herring .…”