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Spatial (depth dependent) and temporal distribution of fish in sandy eulittoral of the tip of the Hel Peninsula (the Gulf of Gdańsk - Baltic)

100%

Sapota M. R.

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2001

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tom Vol. 30, No. 3-4

77-89

EN

Presence of fish from 10 species was confirmed in shallow close to shore waters on the tip of the Hel Peninsula, in period from early spring to late autumn. Zone from shore to 5 meter depth was investigated. The highest number and biomass were noticed in summer on 3 meter depth. As general biodiversity taking into account number increases with increasing depth, whereas biodiversity taking into account biomass is not so depth dependent. Flounder is the absolute dominant at all depths in investigated region. Common goby and three spined stickleback are two other significant species. Comparison of data from all investigated depths shows that sampling in the most close to shore zone (1 meter depth) let well describe fish community of near shore shallow waters in investigated area.

2

Trophic interactions between preadult and adult Pomatoschistus minutus and Pomatoschistus microps and young Platichthys flesus occurring in inshore waters of the Gulf of Gdańsk (Southern Baltic)

63%

Złoch I. , Sapota M. R.

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tom Vol. 39, No.2

37-53

EN

We intended to estimate if shallow inshore waters of the Gulf of Gdańsk can be considered important feeding grounds for the fishes under investigation. We also examined whether competition for food exists between the investigated fishes which co-exist. The study was carried out at Sopot and Chałupy stations from summer 2001 to autumn 2003. The results showed the high importance of Neomysis integer, which exclusively lives in coastal waters, in the diet of all three investigated fish species. It indicates that they utilize this zone as a feeding ground. The obtained dataset also led to the conclusion that fish trophic niches overlap by about 40%.

3

Recrutation and settlement of young flounder (Platichthys flesus) in the western part of the Gulf of Gdańsk (Baltic)

63%

Sapota M. R. , Kamińska U.

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tom Vol. 27, No. 3

31-42

EN

On a basis of whole year monthly sampling, the abundance of the flounder in inshore shallow waters of the western part of the Gulf of Gdansk was established. Flounders were observed almost all year. Only in winter, when sea ice forming proc-esses occurred, they disappeared from the investigated zone. The highest abundance of the flounder was noticed in Hel vicinity. No flounders were observed in inshore waters of the Puck Lagoon. Young flounders occurred in the highest number in July (average for all investigated area amounted to 2.81 individuals 100/ m^2). In that month, this-year-born flounders settle in the inshore shallow water zone. The highest biomass was noticed in August (average 4.98 g/100 m^2) when older bigger flounders more frequently inhabited inshore zone. Body proportions of young flounders during their growth in inshore shallow waters of the Gulf of Gdansk are stable. All measured distances were increasing linearly with the growth of flounder length.

4

Growth of the young flounder (Platichthys flesus) in inshore shallow waters of the Gulf of Gdańsk

63%

Sapota M. R. , Mudrak S.

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tom Vol. 27, No. 3

19-29

EN

The age and rate of growth of the flounder from inshore shallow waters of the Gulf of Gdansk (from shore to 1-m depth) have been investigated. Mainly the flounder from 0 and 1-year age group exists in this zone. Flounders from 0-year age group enter shallow waters of the Gulf of Gdansk in June or July. They stay in this area till the end of the year. Flounders from 1-year age group are represented in the investigated zone all year. Bigger individuals from this group migrate into deeper waters.

5

A study on trash catch of the bottom trawl along Port-Said coast, Egypt

51%

El-Mor M. , El-Etreby S. , Mohammad S. , Sapota M. R.

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2002

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tom Vol. 31, No. 3-4

45-55

EN

The trash catch of an Egyptian Mediterranean trawling net was analyzed. The catch amounted to approximately 15-20 kg per haul, composed of three categories: Juveniles of commercially important species (86.5%), Low-value small size fish species (5.5%) and non-edible species (7.9% of the total trash catch). In the catch, 35 species were identified representing 22 families. Among these, 11 species are known to be of Red Sea origin. The amount of trash catch constituted about 15-20% of the total landing of trawling net. Three species, Diplodus annularis (recruit in July and August), Dicentrarchus punctatus (recruit in June and July) and Sardinella aurita (recruit in September and October) were the most abundant fish species representing 20.5%, 18.9% and 17.9% of the total trash respectively.

6

Biological studies on juvenile fish of Siganus rivulatus (Forsskal 1775) in Port-Said fishing harbour, Egypt

51%

El-Mor M. , El-Etreby S. , Sapota M. R.

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2002

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tom Vol. 31, No. 3-4

17-30

EN

A total of 999 specimens of Siganus rivulatus were collected from trash catches of small beach seine operating in the Port Said fishing harbour at the entrance of the Suez Canal during the period from January to December 1997. The species constituted 20.1% of the trash catch and about 4 - 5% of the total catch of the gear. The juveniles of S. rivulatus could stay at the nursery grounds from October till April, and be recruited from October till December. The length-weight relationships, as well as the condition factor of the juvenile fish, were studied. The feeding activities were quite high in winter months. From May to September, juveniles of S. rivulatus appear to be exclusively deposit feeders in most months, feeding mainly on algae and molluscs.

7

Species composition and size structure of beach seine by-catches in Port-Said fishing harbour, Egypt

51%

El-Mor M. , El-Etreby S. , Sapota M. R.

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2002

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tom Vol. 31, No. 3-4

31-43

EN

The trash catch of the Egyptian Mediterranean small beach seine operating in Port-Said fishing harbour at the entrance of the Suez Canal during the period from January to December 1997 was analyzed. It amounted about 3-5 kg per haul composed of three categories: juveniles of commercially important species (76.6%), low-valued small size fish species (11.2%) and 12.2% of non-edible "trash" species. The amount of trash catch constituted about 20-25% of the total landing of beach seine. It was classified into 42 species representing 24 families. Among these, 17 species are known to be of Red Sea origin. Three species Siganus rivulatus, (recruitment in October), Terapon puta (recruitment in August and September) and Pomadasys incisus (recruitment in January and February) dominated the assemblage of 42 species and contributed 53.8% of all sampled fishes.

8

Diet of the twaite shad Alosa fallax (Lacépčde, 1803) (Clupeidae) in the Gulf of Gdansk, the Baltic Sea

51%

Skóra M. E. , Sapota M. R. , Skóra K. E. , Pawelec A.

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tom Vol. 41, No. 3

24-32

EN

Twaite shad Alosa fallax (12 – 48 cm total length) from the Gulf of Gdansk feed on Mysids: Mysis mixta, Neomysis integer, and fish: Sprattus sprattus, Osmerus eperlanus, and Pomatoschistus sp.. In the stomachs of A. fallax there also occur Hydrobia sp., Diptera and small stones, particles of wood and plastic. The food of inshore twaite shad measured from 12 to 21 cm centered on M. mixta. Fish are the main prey for A. fallax from the class length 22 – 31 cm from the Vistula River mouth and for all shads longer than 32 cm.

9

Modification in the nest guarding strategy - one of the reasons of the round goby (Neogobius melanostomus) invasion success in the Gulf of Gdansk?

51%

Sapota M. R. , Balazy P. , Mirny Z.

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