@article {6665, title = {Digestive enzyme ratios are good indicators of hatchling yolk reserve and digestive gland maturation in early life stages of cuttlefish Sepia officinalis L.: application of these new tools in ecology and aquaculture}, journal = {Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology}, volume = {188}, year = {2018}, pages = {57-76}, abstract = {In Sepia officinalis (Linnaeus, 1758), the digestive gland matures during the first month post-hatching, while a shift from intracellular acid to extracellular alkaline digestion occurs. The purpose of this study was to investigate the possibility of using enzymatic ratios for the description of digestive system maturation in early life stages of S. officinalis. Second, it is intended to apply these new tools as eco-physiological indicators for understanding the impact of cuttlefish eggs{\textquoteright} life history from different spawning sites of the English Channel on digestive performance of juveniles. An experimental rearing was performed over 35\ days after hatching (DAH) on juveniles from wild collected eggs in 2010 and 2011. Four digestive enzyme activities and their ratios [i.e., trypsin, cathepsin, acid (ACP), and alkaline (ALP) phosphatase, ALP/ACP, and trypsin/cathepsin] were studied along with histological features (e.g., internal yolk surface and digestive gland development). The two enzyme ratios were good indicators of digestive system maturation allowing the study of the digestive gland{\textquoteright}s development. They were highly correlated to juveniles{\textquoteright} weight increase and histological features of the gland in early DAH. These ratios described more accurately the shift occurring between the intracellular acid and the extracellular alkaline modes of digestion in S. officinalis and were more specific than separated enzyme activities. Their application as eco-physiological tools revealed that enzyme ratios reflected yolk content and digestive gland development in new hatching juveniles. Finally, ALP/ACP ratio was shown to be a powerful tool to describe growth performance of S. officinalis which is useful for aquaculture optimization. {\textcopyright} 2017, Springer-Verlag GmbH Germany.}, keywords = {Acid Phosphatase, alkaline phosphatase, anatomy and histology, animal, Animals, Aquaculture, cathepsin, Cathepsins, cuttlefish, Gastrointestinal Tract, Physiology, Sepia, Trypsin}, issn = {01741578}, doi = {10.1007/s00360-017-1115-4}, url = {https://link.springer.com/article/10.1007\%2Fs00360-017-1115-4}, author = {Safi, Georges and Anne-Sophie Martinez and Le Pabic, Charles and Le Bihan, E and Jean-Paul Robin and Koueta, Noussith{\'e}} } @article {3900, title = {Stock structure of the {English} {Channel} common cuttlefish {Sepia} officinalis ({Linnaeus}, 1758) during the reproduction period}, journal = {Journal of the Marine Biological Association of the United Kingdom}, year = {2015}, pages = {1{\textendash}10}, abstract = {

Within the English Channel, the common cuttlefish Sepia officinalis is a semelparous species for which a 2-year life cycle was
exclusively described in the 1980s. In the 1990s, new research indicated that whilst a 2-year life cycle was still evident for
females and the large majority of males, a small proportion of males were actually maturing at only 1 year of age. Since
1980, the interest of French and UK fishers for this resource has increased and it is nowadays one of the most important
demersal species of the area and is considered to be fully exploited. From the start of the 20th century, fishing effort
and sea surface temperatures have increased in the English Channel and have probably impacted the life history traits of
S. officinalis. A 2-year sampling programme was undertaken at French landing sites of the English Channel during the reproduction
season in 2010 and 2011 to estimate if the proportion of 1-year-old mature animals has changed. Age determination
was carried out by coupling polymodal decomposition and lipofuscin measurement. Size-at-maturity for each year and each
sex was estimated by fitting a binomial error GLM. Results highlight that a variable percentage of males and females belonging
to the first cohort are mature and that size-at-maturity was lower than that observed in the 1990s. Finally, different parameters,
such as temperature and fishing pressure are explored to discuss changes in life history traits suggesting that cuttlefish
could be an indicator of the temperature regime shift in the English Channel.

}, issn = {0025-3154, 1469-7769}, doi = {10.1017/S0025315415001162}, url = {http://www.journals.cambridge.org/abstract_S0025315415001162}, author = {Gras, Michael and Safi, Georges and Lebredonchel, Hugo and Quinquis, J{\'e}r{\^o}me and Foucher, Eric and Koueta, Noussith{\'e} and Jean-Paul Robin} }