Introduction  fishes in the study area [5-7]. Laith [5] studied asymmetry in some morphological characters of four

1. Introduction  fishes in the study area [5-7]. Laith [5] studied asymmetry in some morphological characters of four

Sparid fishes inhabit tropical and temperate coastal sparid fishes in Benghazi coast. This is the first study water. Fish individuals are swimming near the shore in so far on the feeding habits of Pagrus pagrus (family shallow inlet and bays at moderate depth. Family Sparidae) in Libyan eastern coast. Pagrus pagrus Sparidae comprise about 22 genera in four subfamilies position in the trophic structure of the Libyan eastern containing 41 species [1]. 14 species were recorded in coast is poorly understood. So the aim of the present the Libyan coast, such as Pagrus pagrus, Dentex study is defining the trophic relationships between dentex , Diplodus vulgaris, Lithognathus mormyrus, Pagrus pagrus with other invertebrates and fishes in Oblada melanura , Sarpa salpa and Crenidens this area, in order to understand the dynamic of this crenidens [2]. The red porgy, Pares pagrus is one of regional ecosystem. Beside results from feeding habits the fishes in family Sparidae, is one of the most popular of Pagrus pagrus may have direct implications for sparid fish species in the Mediterranean region and the

aquaculture.

Atlantic coast [3], the fish had been characterised by high price value, a highly appreciated flesh and good

2. Materials and Methods

market perspectives. Although the red porgy found in a Monthly samples of Pagrus pagrus were collected

wide variety of locations that range from Europe to the during the period from January to December 2008 by Caribbean, its status is considered endangered [4]. using gill and trammel nets from artisanal fishing in From the available literature, it was found that few Benghazi fishing harbour 32°36'N and 20°03'E on the works have been published on the biology of Sparid Mediterranean (Fig. 1). A total of 500 specimens

Corresponding author: Mohammad El-Mor, Ph.D., lecturer, of Pagrus pagrus were sampled for studying the research fields: fisheries and fish biology. E-mail:

feeding habits.

melmor88@yahoo.com.

Feeding Habits of the Red Porgy Pagrus pagrus (Linnaeus, 1758) from Benghazi Coasts, Libya

Fig. 1 Benghazi fishing harbor, on the Mediterranean, Libya.

Annual diet composition, seasonal variations of diet, However, crustaceans supplemented by molluscs variations of diet with lengths and feeding intensity

formed the major food groups for Pagrus pagrus. were estimated in this study. For each fish specimen,

Crustaceans made up of 38.3% by volume composition total length measured to the nearest 0.1 cm. Each fish

of the bulk of the diet which represented by small was dissected and the alimentary tract removed and

prawns and crabs, whereas molluscs (13.2%) coming preserved in formalin. The degree of fullness of the

in the second position of importance and were stomach was assessed by visual estimation and

composed of bivalves and gastropods. The other food classified as empty, trace, quarter full, half full, three

items were echinoderms constituting 11.4%, this quarters full and completely full respectively as

followed by polychaetes (10.7%), digestive food (10.3%), described in Ref. [8]. Food items were identified to

the fish parts (7.1%) including fish scales and bones, their groups. A list of general diet composition was made.

this followed by seagrasses (6.4%), which was mainly Food analysis was made by points of assessment [9, 10].

represented by Halophila stipulacea and Halophila The results were statistically analysis subjected to the

ovalis . The minor food items were sediments (sand and further statistical treatment according to Godfriaux [11],

clay) constituting 2.7 %.

in order to give more precise information about

3.2 Monthly Variations in Diet Composition food and feeding habits of Pagrus pagrus.

Food items were occurred in all year round during

3. Results

the study (Table 1), crustaceans, echinoderms and fish parts constituted the major food item all year round

3.1 Annual Diet Composition during the study. Crustaceans increased from 29% in

The variety of food items was large (Fig. 2.). January to 59.2% in September, then decreased in the

70 Feeding Habits of the Red Porgy Pagrus pagrus (Linnaeus, 1758) from Benghazi Coasts, Libya

Fig. 2 The diet composition of Pagrus pagrus from Benghazi coast, 2008.

Table 1 Monthly variations in diet composition of Pagrus pagrus from Benghazi coast, Libya.

Food items

Month No. Crustaceans Molluscs Echinoderms Polychaetes Digestive food Fish parts Seagrasses Sediments

11.6 0.8 A May 50 35.4

28.6 3.0 A 28.6 3.0 0.2 1.2 June 50 32.2

2.4 A 1.2 July 22 38.0

0.3 40.0 0.1 0.2 0.2 AA Oct. 25 48.0

A 15.2 11.2 A 5.6 12.1 8.0 Nov.

50 39.6 16.4 6.8 19.1 3.6 4.4 6.0 4.0 Dec.

13 32.3 4.2 23.1 15.4 12.3 2.0 6.2 4.6 Data expressed as percentage; A: No food in class occurred.

following months. Molluscs the second category in and 15.4% in December. The digestive food attained food items occurred in all months except in October,

the maximum value in May 28.6% whereas the reaching the maximum value in June (39.6%) and the

minimum value was in September (0.2%), absent in lowest value was observed in September (0.3).

October and raised in November and December by Echinoderms ingested showed the highest value in

3.6% and 12.3% respectively. Fish parts increased September (40.0%) and lowest value in March (1.0%).

from 0.8% in January to 20.0% in February then Polychaetes food item absent in May and its values

decreased in the following months reaching 2.0% in decreased from 33.1% in January to 0.1% in September

December. Seagrasses disappeared in June and and recorded 11.2% in October, 19.1% in November

September reaching the maximum values in July

71 22.6% and August 27.5% and the lowest value was

Feeding Habits of the Red Porgy Pagrus pagrus (Linnaeus, 1758) from Benghazi Coasts, Libya

digestive food increased from 6.8% in size class observed in November 6.0% and December 6.2%.

(15.5-16.8 cm) to 27.4% in size class (29.5-30.8 cm). Sediments ingested showed the highest values in

Fish parts increased from 0.2% in size class October 8.0% and the lowest value was observed in

(14.4-15.4 cm) to 17.45% in size class (29.5-30.8 cm). November (4.0%) and December (4.6%).

Seagrasses decreased from 30.1% in size class (14.1-15.4 cm) to 0.6% in size class (25.3-28.0 cm) and

3.3 Feeding Habits in Relation to Fish Size completely absent in the following length groups.

The length groups of Pagrus pagrus population Sediments decreased from 12.6% in size class classified into fourteen classes ranged from 11.3 cm to

(15.5-16.8 cm) to 2.2% in size class (23.9-25.2 cm) and

30.8 cm with 1.3 cm interval (Table 2). Prey size completely absent in the following length groups. differed between large sizes fishes, which had ingested

3.4 Feeding Intensity

the large size, prey, whereas the small sized fishes ingested the small size prey. Crustaceans were found in

Fishes with stomach half full, almost full and full of all length groups of Pagrus pagrus, they decreased

food ranked b% constituted 40.3% of all analyzed from 100% in size class (11.3-12.6 cm) to 1.5% in size

individuals, whereas those with stomachs that were class (29.5-30.8 cm). Molluscs increased from 7.9% in

empty or with traces of food ranked in a%, represented size class (14.1-15.4 cm) to 36.9% in size class

59.7% of the total specimens (Table 3). The feeding (25.3-26.6 cm) then decreased in the following size

activities were quite high during summer and early class’s to 23.6% in size class (29.5-30.8 cm).

autumn months, in July (60.9%), August (65.0%) and Echinoderms increased from 0.5% in size class

September (64.0%). There are minimal rate of feeding (14.1-15.4 cm) to 30.1% in size class (29.5-30.8 cm).

intensity in the end of autumn, winter, spring and early Polychaetes decreased from 25.9% in size class

summer seasons, where the stomachs were empty, (12.7-14.0 cm) to 0.5% in size class (26.7-28.0 cm) and

trace and quarter full ranged from 74.0% in April, completely absent in the following length groups. The

80.5% in May and 86.0% in June.

Table 2 The diet composition of different size classes (L t , cm) Pagrus pagrus Benghazi coast, Libya.

Size groups

Food items

(cm) No. Crustaceans Molluscs Echinoderms Polychaetes Digestive food Fish parts Seagrasses Sediments

11.3-12.6 3 100.0 A A A A A A A 12.7-14.0 18 74.1

A A 25.9 A A A A 14.1-15.4 23 52.7

7.9 0.5 8.6 A 0.2 30.1 A 15.5-16.8 27 30.0

19.2 9.1 0.8 A 26.7-28.0 5 6.2

22.4 10.4 0.6 A 28.1-29.4 2 4.3

23.5 29.1 A 26.8 16.3 A A 29.5-30.8 2 1.5

23.6 30.1 A 27.4 17.4 A A Data expressed as percentage; A: No food in class occurred.

72 Feeding Habits of the Red Porgy Pagrus pagrus (Linnaeus, 1758) from Benghazi Coasts, Libya

Table 3 Monthly variation in the intensity of feeding of Pagrus pagrus from Benghazi coast, Libya.

The degree of distension of the stomach

Months No.

Empty Trace 1/4 a %

1/2 3/4 Full b% Jan. 50 16.0 22.0 26.0 64.0 26.0 10.0 A 36.0 Feb. 50 8.0 20.0 20.0 48.0 24.0 28.0 A 52.0 Mar. 50 10.0 26.0 26.0 62.0 20.0 10.0 8.0 38.0 Apr. 50 12.0 40.0 22.0 74.0 18.0 8.0 A 26.0

May 50 12.0 48.5 20.0 80.5 17.5 A 2.0 19.5 Jun. 50 6.0 30.0 50.0 86.0 14.0 A A 14.0 Jul. 22 8.9 A 30.1 39.0 26.2 13.0 21.7 60.9 Aug. 40 10.0 10.0 15.0 35.0 25.0 20.0 20.0 65.0

Sep. 50 16.0 2.0 18.0 36.0 26.0 22.0 16.0 64.0 Oct. 25 12.0 20.0 32.0 64.0 28.0 A 8.0 36.0 Nov.

50 10.0 5.0 43.0 58.0 2.0 40.0 A 42.0 Dec. 13 15.4 15.4 38.5 69.3 23.2 7.5 A 30.7

Data expressed as percentage; A: No food in class occurred.

red porgy and they concluded that the number and