2019
 

Population genomics and phylogeography of a benthic coastal shark (Scyliorhinus canicula) using 2b-RAD single nucleotide polymorphisms

År: 2019

Population genomics and phylogeography of a benthic coastal shark (Scyliorhinus canicula) using 2b-RAD single nucleotide polymorphisms

Manuzzi, A., Zane, L., Munoz-Merida, A., Griffiths, A. M. & Veríssimo, A. 2019 (Accepted/In press) In : Biological Journal of the Linnean Society.

Research output: Research - peer-reviewJournal article – Annual report year: 2019

Original languageEnglish
JournalBiological Journal of the Linnean Society
ISSN0024-4066
DOIs
StateAccepted/In press - 2019

 

Diel vertical feeding behaviour of Atlantic mackerel (Scomber scombrus) in the Irminger current

År: 2019

Diel vertical feeding behaviour of Atlantic mackerel (Scomber scombrus) in the Irminger current

Jansen, T., Post, S., Olafsdottir, A. H., Reynisson, P., Óskarsson, G. J. & Arendt, K. E. 2019 In : Fisheries Research. 214, p. 25-34

Research output: Research - peer-reviewJournal article – Annual report year: 2019

The main prey of the Atlantic mackerel undertake diel vertical migrations, however diel and vertical patterns in the feeding by mackerel remains poorly known thus limiting our understanding and quantification of ecosystem trophodynamics and potentially influencing stock assessment and ecosystem based management. By intensive monitoring of adult Atlantic mackerel and its prey during summer in the Irminger Sea, it was found that the diel feeding cycle is of high quantitative importance. Fresh stomach content analysis indicated a marked diel pattern with copepods as the main prey between 16 and 24 (solar time), and euphausiids/myctophids between 22 and 08. Compared with the zooplankton distribution and composition, there were no indications of feeding below the mixed layer. Mackerel selected for the largest and most energy rich prey, namely copepods with prosome lengths>2 mm, and then switched from copepods to euphausiids/myctophids around midnight, despite that the copepods were also aggregated during night. Stomach fullness increased significantly with length and condition, suggesting that individuals that were larger were more effective feeders. The stomach content by weight primarily consisted of copepods (65%, exclusively Calanus finmarchus), euphausiids (18%), and to a lesser extent teleosts (5%, mainly myctophids), hyperiids (4%) and cephalopods (2%). The results are likely widely applicable in the main feeding season and areas (the oceanic parts of the Nordic Seas during summer), because of similarities in the diet of the adult mackerel and in the prey’s diel vertical migration. In conclusion, it is imperative to account for the diel dynamics when quantifying the mackerel diet and its impact on prey populations
Original languageEnglish
JournalFisheries Research
Volume214
Pages (from-to)25-34
ISSN0165-7836
DOIs
StatePublished - 2019

 

Proactive coping style in early emerging rainbow trout carries a metabolic cost with no apparent return

År: 2019

The timing with which salmonid larvae emerge from their gravel nests is thought to be correlated with a particular suite of behavioural and physiological traits that correspond to the stress coping style of the individual. Among these traits, aggressiveness, dominance and resilience to stress, are potentially interesting to exploit in aquaculture production. In the present study a series of experiments were performed, with the purpose of characterising behavioural, metabolic and production related traits in rainbow trout juveniles from different emergence fractions. Newly hatched rainbow trout were sorted according to their emergence time from an artificial redd. The early, middle, and late fractions were retained and assessed for their physiological response to stress, growth performance, metabolism, fasting tolerance, and potential for compensatory growth. The early emerging fraction showed proactive behavioural traits; they were faster to reappear following startling, showed a reduced cortisol response following stress, and a reduced metabolic cost of recovery. Emergence time was not correlated with any differences in standard or maximum metabolic rates, but was however, correlated with higher routine metabolic rates, as demonstrated by significantly bigger weight losses during fasting in the early emerging group. Growth rates and feed conversion efficiencies were not significantly different when fish were co-habitated under a restrictive feeding regime, suggesting that early emerging fish are not able to monopolise food resources. The intermediate emerging group, which makes up the bulk of a population and is often ignored, appears to possess the best growth performance traits, possibly because they do not expend excessive energy on dominance behaviour such as the early emerging group, while they are also not overly timid or stress prone such as the late emerging group.
Original languageEnglish
JournalComparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
Volume231
Pages (from-to)104-110
ISSN1095-6433
DOIs
StatePublished - 2019

 

Produktion af østersyngel (Ostrea edulis) – en nøglefaktor i såvel naturgenopretning som akvakultur

År: 2019

Produktion af østersyngel (Ostrea edulis) – en nøglefaktor i såvel naturgenopretning som akvakultur

Møller, L. F. 2019

Research output: ResearchConference abstract for conference – Annual report year: 2019

Original languageEnglish
Publication date2019
StatePublished - 2019
EventDansk Havforskermøde 2019 - Syddansk Universitet, Odense, Denmark
Duration: 23 Jan 201925 Jan 2019

Conference

ConferenceDansk Havforskermøde 2019
LocationSyddansk Universitet
CountryDenmark
CityOdense
Period23/01/201925/01/2019