Abstract
This study, based on data and observations from commercial fishing contributions in
the Bouharoun region and surveys carried out by the CNRDPA oceanographic vessel
during the Algerian-Spanish cooperation campaign, provides information on the
distribution, ecology, diet, reproduction, growth and exploitation of white shrimp
(Parapenaeus longirostris, Lucas 1846) and red shrimp (Aristeus antennatus, Risso
1816) in the trawlable bottoms of the Algerian coast. These two species of deep-sea
shrimp, of great economic importance, are widespread and abundant in Algerian waters.
The ecological and biological studies carried out on these shrimp have made it possible
to specify the optimal conditions for their distribution. Aristeus antennatus mainly
occupies trawlable bottoms between 200 and 600 meters deep, while Parapenaeus
longirostris is mainly found on muddy, more or less sandy bottoms, at depths varying
between 150 and 350 meters. Between February 2024 and May 2024, 704 individuals
of white shrimp (including 330 females and 374 males) and 712 individuals of red
shrimp (including 144 females and 570 males) were measured from commercial catches
in the central region of the Algerian coast. The overall sex ratio is almost equal in white
shrimp, with a similarity in average sizes between males and females. In contrast, in
red shrimp, females have a significantly larger mean size than males. Growth
parameters calculated for both sexes combined in Parapenaeus longirostris are: L∞ =
38.09 mm, K = 0.56 year-1 and t0 = -0.26 year. For Aristeus antennatus, growth
parameters differ according to sex: in females, L∞ = 69.43 mm, K = 0.42 year-1 and t0
= -0.31 year, and in males, L∞ = 46.87 mm, K = 0.44 year-1 and t0 = -0.3 year. These
results were used to estimate exploitation parameters. For Parapenaeus longirostris,
the total mortality coefficient (Z) is 1.66 yr-1, natural mortality (M) is 0.64 yr-1, fishing
mortality (F) is 1.04 yr-1, with an exploitation rate (E) of 0.62. For Aristeus antennatus,
the total mortality coefficients are Z = 2.1 yr-1 for females and Z = 2.26 yr-1 for males,
natural mortality is M = 0.44 yr-1 for females and M = 0.52 yr-1 for males, while fishing
mortality is F = 1.62 yr-1 for females and F = 1.79 yr-1 for males, with exploitation
rates of E = 0.77 for females and E = 0.79 for males. These results allowed studying the
yield per recruit for both species, revealing that the current fishing effort is close to the
optimal effort, which suggests an overexploitation of the stocks. The analysis of the
hourly yield of Parapenaeus longirostris showed a peak in 2008 and 2009 with 16 kg/h
at the port of Algiers and Cherchell respectively, while the port of Bouharoun recorded
a significant hourly yield of 12 kg/h for this species in 2009, 2016 and 2019. For
Aristeus antennatus, the highest hourly yield was observed in 2008 at the port of
Cherchell with 24 kg/h.
Keywords: Parapenaeus longirostris, Aristeus antennatus, growth, natural mortality,
fishing
mortality,
exploitation,
central
Algeria.
This study, based on data and observations from commercial fishing contributions in
the Bouharoun region and surveys carried out by the CNRDPA oceanographic vessel
during the Algerian-Spanish cooperation campaign, provides information on the
distribution, ecology, diet, reproduction, growth and exploitation of white shrimp
(Parapenaeus longirostris, Lucas 1846) and red shrimp (Aristeus antennatus, Risso
1816) in the trawlable bottoms of the Algerian coast. These two species of deep-sea
shrimp, of great economic importance, are widespread and abundant in Algerian waters.
The ecological and biological studies carried out on these shrimp have made it possible
to specify the optimal conditions for their distribution. Aristeus antennatus mainly
occupies trawlable bottoms between 200 and 600 meters deep, while Parapenaeus
longirostris is mainly found on muddy, more or less sandy bottoms, at depths varying
between 150 and 350 meters. Between February 2024 and May 2024, 704 individuals
of white shrimp (including 330 females and 374 males) and 712 individuals of red
shrimp (including 144 females and 570 males) were measured from commercial catches
in the central region of the Algerian coast. The overall sex ratio is almost equal in white
shrimp, with a similarity in average sizes between males and females. In contrast, in
red shrimp, females have a significantly larger mean size than males. Growth
parameters calculated for both sexes combined in Parapenaeus longirostris are: L∞ =
38.09 mm, K = 0.56 year-1 and t0 = -0.26 year. For Aristeus antennatus, growth
parameters differ according to sex: in females, L∞ = 69.43 mm, K = 0.42 year-1 and t0
= -0.31 year, and in males, L∞ = 46.87 mm, K = 0.44 year-1 and t0 = -0.3 year. These
results were used to estimate exploitation parameters. For Parapenaeus longirostris,
the total mortality coefficient (Z) is 1.66 yr-1, natural mortality (M) is 0.64 yr-1, fishing
mortality (F) is 1.04 yr-1, with an exploitation rate (E) of 0.62. For Aristeus antennatus,
the total mortality coefficients are Z = 2.1 yr-1 for females and Z = 2.26 yr-1 for males,
natural mortality is M = 0.44 yr-1 for females and M = 0.52 yr-1 for males, while fishing
mortality is F = 1.62 yr-1 for females and F = 1.79 yr-1 for males, with exploitation
rates of E = 0.77 for females and E = 0.79 for males. These results allowed studying the
yield per recruit for both species, revealing that the current fishing effort is close to the
optimal effort, which suggests an overexploitation of the stocks. The analysis of the
hourly yield of Parapenaeus longirostris showed a peak in 2008 and 2009 with 16 kg/h
at the port of Algiers and Cherchell respectively, while the port of Bouharoun recorded
a significant hourly yield of 12 kg/h for this species in 2009, 2016 and 2019. For
Aristeus antennatus, the highest hourly yield was observed in 2008 at the port of
Cherchell with 24 kg/h.
Keywords: Parapenaeus longirostris, Aristeus antennatus, growth, natural mortality,
fishing
mortality,
exploitation,
central
Algeria.