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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)

Złoch I., Sapota M.R.

Oceanological and Hydrobiological Studies

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2010

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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%.

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Diel food composition and changes in the diel and seasonal feeding activity of common goby, sand goby and young flounder inhabiting the inshore waters of the Gulf of Gdańsk, Poland

Złoch I., Sapota M., Fijałkowska M.

Oceanological and Hydrobiological Studies

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2005

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Vol. 34, No.3

69--84

EN

A study was conducted from 2001 to 2003 in the Gulf of Gdańsk (Poland) on the diel food composition and diel and seasonal changes in the feeding activity of Pomatoschistus minutus, Pomatoschistus microps, and Platichthys flesus. During the three-year study, no empty fish stomachs were noted, and the fish food was comprised exclusively of prey species that inhabit the shallow water zone (e.g., Bathyporeia pilosa). It can also be stated that the shallow waters of the Gulf of Gdańsk are an important feeding ground for Pomatoschistus sp. and P. flesus. The food intake of all three investigated fish was lower at night than during the day, which led to the conclusion that these fish are day feeders. The seasonal feeding intensity of the sand and common gobies was approximately the same throughout the investigation but was higher in April, June, and August, and lower in September. The flounder fed most intensively in August and March, while feeding intensity was lower in May and June. In September 2001, the most important prey items for P. minutus were Amphipoda undet. and Mysidacea undet. in the morning, N. integer and Mysidacea undet. at noon, and Harpacticoida and Copepoda undet. in the evening. In the same month, P. microps fed mainly on B. pilosa at 08:00, N. integer at 00:00, and Harpacticoida at 20:00. From 2001 to 2003, P. flesus preyed mainly on Polychaeta in the morning hours, while in the evening it targeted N. integer according to the prey frequency of occurrence and quantity in the fish stomachs.

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Seasonal and daily distribution of commercial and non-commercial fish in shallow inshore waters of the Gulf of Gdańsk

Lizińska A.

Oceanological Studies

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2002

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Vol. 31, No. 1-2

31-42

EN

Seasonal and daily changes in the fish community and variations between commercial and non-commercial fish abundance were monitored in the inshore waters of the western part of the Gulf of Gdask (the Sopot territory). Samples were collected from December 1998 to December 1999, though monthly samplings, and supplemented by 24-hour investigations taken every three months, using a two-meter wide trawl. Among the 16 species collected, 5 were commercial and 11 were non-commercial. Juvenile forms of herring and flounder dominated the commercial fish; the highest catches were in March (89 ind. 100 m-2). Among the non-commercial fish, two species of Gobiidae (sand and common goby), and three-spine stickleback were most frequently caught. During the 24hour observations, commercial fish were noticed mostly at night. The investigated area is an important zone for both juvenile commercial fish and some ecologically important uncomercial species.

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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)

Sapota M.R.

Oceanological Studies

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2001

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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.