249
1
Bremen Marine Ecology (BreMarE), Marine Zoology,
University of Bremen, P.O. Box 330440, 28334 Bremen,
Germany
2
Alfred Wegener Institute, Helmholtz Centre for Polar
and Marine Research, P.O. Box 120161, 27570 Bremerhaven,
Germany
*corresponding author: eleni.melis@uni-bremen.de
Keywords: Brown shrimp, Fatty acid composition,
Midgut gland and eggs, Lipid transfer, Capital and income
breeding
The brown shrimp Crangon crangon inhabits European
coastal areas within a large latitudinal range. It also inhabits the North Sea, a habitat with pronounced seasonal fluctuations. In spite of its high ecological and economical
value, our knowledge about adaptive processes and strategies of C. crangon to cope with these changing conditions
is scarce. In marine decapods, lipids are mainly stored in
the midgut gland and used as major energy source for
numerous metabolic processes, including reproduction.
Many decapods are capital breeders, using lipid deposits
from the midgut gland to fuel egg production. During
oogenesis in C. crangon, a significant share of the lipid
stores is suggested to be transferred from the midgut gland
to the developing eggs. This would indicate that C. crangon
also follows the strategy of capital breeding. This study
aims at elucidating lipid transfer and breeding strategy of
C. crangon. Total lipid contents and fatty acid (FA) compositions of midgut glands and early developmental eggs
were determined and compared. Gas chromatography and
principal component analysis (PCA) were used to determine differences in FA composition between midgut glands
and eggs. Comparison of total lipid levels did not reveal
significant differences between the two tissues. However,
PCA based on FA composition clearly separated two clusters, grouping samples of the same tissues. Hence, C. crangon may either follow the income breeding strategy, with
FAs in the eggs originating from recently ingested food
items, or capital breeding, with a transfer of deposited FAs
from the midgut gland to the eggs. The capacity to utilize
the benefits of either reproductive strategy may offer a
selection advantage in variable habitats.
15.2.12 Biology and Population Dynamics
of Sardinella aurita in South Morocco
A. Baali
1*
, H. Bourassi
1
, N. Charouki
2
, K. Manchih
2
,
K. Amenzoui
2
, A. Yahyaoui
1
1
Zoology and General Biology Laboratory, Faculty of
Science, Mohammed V University, Rabat, Morocco
2
Fishery Research National Institute, Casablanca,
Morocco
*corresponding author: ayoubbaali22@gmail.com
Keywords: Sardinella aurita, Reproduction biology,
Population dynamics, Gonadosomatic index, Sea Surface
Temperature, South of Morocco
Round sardinella (Sardinella aurita) has gained much
attention lately because of its biomass decrease, which
might be the result of climatic changes occurring across
the Atlantic Sea. Little information is known about the
biology of this species in the Moroccan Atlantic area. This
lack of study is rather surprising given the considerable
catches of the round sardinella and the strong contributions in the total catch in last years in particular in the
southern Moroccan Atlantic. The objective of this study
was to explore some aspects of the reproductive biology of
Sardinella aurita and to understand recent biomass
decrease using monthly landed catch and Sea Surface
Temperature (SST) data from 2009 to 2016. To fill the
knowledge gaps in round sardinella biology, our study
investigated this species population dynamics in the South
of Morocco. Using a Chi test, we first investigated the
overall female to male ratio, which was not statistically
different, although it varied seasonally and according to
the length of the fish. The monthly changes in the gonadosomatic index and the macroscopic characteristics of
gonads showed that round sardinella have spawning peak
on April in this area. They were no differences in size at
maturation between sexes (p > 0.05) while females reach
sexual maturity at a smaller size than males (26.17 and
26.78 cm respectively). Regarding the SST and biomass of
the round sardinella we observed that we have a high correlation coefficient between the two parameters especially
in the 22° of latitude, which allows us to say that the temperature influences the presence of this species in the present area and to conclude that the global warming impact
Moroccan fisheries.
15.2.13 To Feed or not to Feed? Artificial Feeding
Affects Reef Fish Functions
Natalie Prinz
1,2*
, Sebastian C. A. Ferse
2
, Sonia Bejarano
2
1
University of Bremen, Bibliothekstraße 1, 28359
Bremen, Germany
2
Leibniz Center for Tropical Marine Research (ZMT)
Fahrenheitstraße 6, 28359 Bremen, Germany
*corresponding author: nprinz@uni-bremen.de
Keywords: Coral reef tourism, Supplementary feeding,
Fish feeding rates, Functional groups, South-Pacific
Over centuries humans have fed wild animals, driven by
the desire to provoke close contact. Artificial feeding has
become a regular habit in ecotourism activities worldwide,
with poorly known consequences for ecosystem function.
This study quantifies for the first time (1) how effective is
artificial feeding at attracting reef fishes, (2) which feeding
guilds are most attracted, and (3) how are natural levels of
corallivory and grazing-detritivory affected. Data were collected in sites where fish are regularly fed bread by snorkelers, and adjacent control sites, where bread was only provided
for this study, within the Aitutaki lagoon (Cook Islands). The
fish community was censused and feeding rates (bread verAppendices
1
Bremen Marine Ecology (BreMarE), Marine Zoology,
University of Bremen, P.O. Box 330440, 28334 Bremen,
Germany
2
Alfred Wegener Institute, Helmholtz Centre for Polar
and Marine Research, P.O. Box 120161, 27570 Bremerhaven,
Germany
*corresponding author: eleni.melis@uni-bremen.de
Keywords: Brown shrimp, Fatty acid composition,
Midgut gland and eggs, Lipid transfer, Capital and income
breeding
The brown shrimp Crangon crangon inhabits European
coastal areas within a large latitudinal range. It also inhabits the North Sea, a habitat with pronounced seasonal fluctuations. In spite of its high ecological and economical
value, our knowledge about adaptive processes and strategies of C. crangon to cope with these changing conditions
is scarce. In marine decapods, lipids are mainly stored in
the midgut gland and used as major energy source for
numerous metabolic processes, including reproduction.
Many decapods are capital breeders, using lipid deposits
from the midgut gland to fuel egg production. During
oogenesis in C. crangon, a significant share of the lipid
stores is suggested to be transferred from the midgut gland
to the developing eggs. This would indicate that C. crangon
also follows the strategy of capital breeding. This study
aims at elucidating lipid transfer and breeding strategy of
C. crangon. Total lipid contents and fatty acid (FA) compositions of midgut glands and early developmental eggs
were determined and compared. Gas chromatography and
principal component analysis (PCA) were used to determine differences in FA composition between midgut glands
and eggs. Comparison of total lipid levels did not reveal
significant differences between the two tissues. However,
PCA based on FA composition clearly separated two clusters, grouping samples of the same tissues. Hence, C. crangon may either follow the income breeding strategy, with
FAs in the eggs originating from recently ingested food
items, or capital breeding, with a transfer of deposited FAs
from the midgut gland to the eggs. The capacity to utilize
the benefits of either reproductive strategy may offer a
selection advantage in variable habitats.
15.2.12 Biology and Population Dynamics
of Sardinella aurita in South Morocco
A. Baali
1*
, H. Bourassi
1
, N. Charouki
2
, K. Manchih
2
,
K. Amenzoui
2
, A. Yahyaoui
1
1
Zoology and General Biology Laboratory, Faculty of
Science, Mohammed V University, Rabat, Morocco
2
Fishery Research National Institute, Casablanca,
Morocco
*corresponding author: ayoubbaali22@gmail.com
Keywords: Sardinella aurita, Reproduction biology,
Population dynamics, Gonadosomatic index, Sea Surface
Temperature, South of Morocco
Round sardinella (Sardinella aurita) has gained much
attention lately because of its biomass decrease, which
might be the result of climatic changes occurring across
the Atlantic Sea. Little information is known about the
biology of this species in the Moroccan Atlantic area. This
lack of study is rather surprising given the considerable
catches of the round sardinella and the strong contributions in the total catch in last years in particular in the
southern Moroccan Atlantic. The objective of this study
was to explore some aspects of the reproductive biology of
Sardinella aurita and to understand recent biomass
decrease using monthly landed catch and Sea Surface
Temperature (SST) data from 2009 to 2016. To fill the
knowledge gaps in round sardinella biology, our study
investigated this species population dynamics in the South
of Morocco. Using a Chi test, we first investigated the
overall female to male ratio, which was not statistically
different, although it varied seasonally and according to
the length of the fish. The monthly changes in the gonadosomatic index and the macroscopic characteristics of
gonads showed that round sardinella have spawning peak
on April in this area. They were no differences in size at
maturation between sexes (p > 0.05) while females reach
sexual maturity at a smaller size than males (26.17 and
26.78 cm respectively). Regarding the SST and biomass of
the round sardinella we observed that we have a high correlation coefficient between the two parameters especially
in the 22° of latitude, which allows us to say that the temperature influences the presence of this species in the present area and to conclude that the global warming impact
Moroccan fisheries.
15.2.13 To Feed or not to Feed? Artificial Feeding
Affects Reef Fish Functions
Natalie Prinz
1,2*
, Sebastian C. A. Ferse
2
, Sonia Bejarano
2
1
University of Bremen, Bibliothekstraße 1, 28359
Bremen, Germany
2
Leibniz Center for Tropical Marine Research (ZMT)
Fahrenheitstraße 6, 28359 Bremen, Germany
*corresponding author: nprinz@uni-bremen.de
Keywords: Coral reef tourism, Supplementary feeding,
Fish feeding rates, Functional groups, South-Pacific
Over centuries humans have fed wild animals, driven by
the desire to provoke close contact. Artificial feeding has
become a regular habit in ecotourism activities worldwide,
with poorly known consequences for ecosystem function.
This study quantifies for the first time (1) how effective is
artificial feeding at attracting reef fishes, (2) which feeding
guilds are most attracted, and (3) how are natural levels of
corallivory and grazing-detritivory affected. Data were collected in sites where fish are regularly fed bread by snorkelers, and adjacent control sites, where bread was only provided
for this study, within the Aitutaki lagoon (Cook Islands). The
fish community was censused and feeding rates (bread verAppendices