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Hydroid Gonothyraea loveni found on the straightnose pipefish (Nerophis ophidion) in the Gulf of Gdańsk : symbiosis, parasitism or biofouling?

Dziubińska A., Sapota M.

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

332--335

EN

Straightnose pipefish (Nerophis ophidion), covered with hydroid Gonothyraea loveni, were caught in August 2010 near Gdynia while fishing with fyke nets. The hydroid colonies were spaced around the fish, from the head to the anus. These colonies seemed to cause serious problems with the balance and swimming ability of the fish. It appears that there are no symbiotic or parasitic relationships between the hydroid and the fish. The fish was probably just another substrate for G. loveni and became colonized by fouling on the skin surface. It should also be taken into consideration that hydroid colonies can move from place to place with their fish host. It is possible that the hydroid benefits from the fish active search for planktonic food.

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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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Predictional model of biocenotic changes in offshore baltic plankton due to temperature increase

Pliński M., Żmijewska M. I., Sapota M., Witek B., Mudrak S.

Oceanological and Hydrobiological Studies

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2003

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Vol. 32, No. 3

29-41

EN

Over the last 20 years, more and more reliable data concerning global climate change, mainly climate warming, have become available in the literature. Change such as this has also been documented in the Gulf of Gdańsk. Climate change has an influence on aquatic ecosystems and especially their biocoenoses, and plankton is one of its most sensitive ecological fractions. Positive and negative statistical correlation in the exclusive relationship between the quantity of plankton groups and water temperature has been observed. When time was applied as a factor, only the annual increments of the blue-green algae correlation were statistically significant, and the regression equation calculated in this paper was applied to predict a rise in the population number of this algae in response to increasing temperature. It was not possible to perform this calculation with the other plankton components.