Use of an ultrasound device to determine sex and to perform gonad biopsy in the European eel Anguilla Anguilla

Abstract

The European eel Anguilla anguilla is a highly important market species which is also increasingly in danger of extinction in Europe. One of the ways of protecting the species in the natural environment, while maintaining its market supply, is its aquaculture, e.g. due to much higher survival rate under controlled conditions than in the wild. However, this can be done only when an effective artificial reproduction biotechnique is developed. The aim of this study was to use an ultrasound device to determine the sex and to perform a biopsy of the gonads, which is a part of complete protocol of eel artificial reproduction. The findings indicate that ultrasonography is highly useful in determining the sex in migrating eel (100% of sureness) and in performing high-precision biopsy of the gonads. The present method gives the possibility to quick determine the maturity of the female gonads. The application of ultrasonography (USG) is totally safe for fish and a portable ultrasound device can be used in both the laboratory and in the field. Keywords: European eel. Oocytes. Maturation. Sex. Ultrasonography. USG. ResumoA Enguia-Européia Anguilla anguilla é uma espécie de grande importância comercial e que apresenta também grande risco de extinção na Europa. Uma das formas para a proteção das espécies em seu ambiente natural e de manter o seu suprimento no comércio é a aquicultura, por exemplo, devido à taxa de sobrevivência em condições controladas ser muito superior a existente em condições naturais. Contudo isto só pode ser obtido quando é desenvolvida uma biotécnica de reprodução artificial eficiente. O presente trabalho foi delineado para utilizar um dispositivo ultrassonográfico a fim de determinar o sexo e de possibilitar a realização de biópsias das gônadas, o que é parte do protocolo complete de reprodução artificial de enguias. As constatações indicaram que a ultrassonografia é muito útil para a determinação do sexo das enguias (100% de exatidão) e também é capaz de possibilitar a realização de uma biópsia das gônadas de alta precisão. O método descrito oferece possibilidades para a rápida determinação da maturidade das gônadas das fêmeas. A aplicação da ultrassonografia é totalmente segura para peixes e o dispositivo portátil de ultrassonografia pode ser utilizado tanto no laboratório como em condições de campo. Palavras-chave: Enguia-Européia. Maturação. Sexo. Ultrassonografia. USG.

Early sex identification of 18‐month cultured beluga sturgeon (Huso huso) using ultrasonography, small surgery and plasma steroid hormones

“…These findings were proved by previous studies considering the small surgery as an effective method to determine the sex gender in Acipenser nudiventris (Hallajian et al, ) and Epinephelus merra (AshrafulAlam & Nakamura, ). The effectiveness of sex determination with accuracy 95% and 100% was reported in sexually immature and mature European eel, respectively (Kucharczyk et al, ). Falahatkar et al () reported sex determination of 3‐year‐old fish as 89.7%, 6‐year‐old fish as 95.4%, and 100% accuracy for 14‐year‐old fish, which were successfully identified through the biopsy procedure in the beluga sturgeon.…”

“…USG was found to be effective in determining the sex of fish in the three‐year‐old beluga in which females and males were identified with 96.7% and 97.9% accuracy, respectively (Masoudifard et al, ). Furthermore, the USG method was successful in determining the sex of European eel ( Anguilla anguilla ) (Kucharczyk et al, ) and shovelnose sturgeon (Robert et al, ). In one study on shovelnose sturgeon, 86% accuracy was obtained with using the ultrasound method (Colombo et al, ).…”

Sex identification in immature Eurasian perch ( Perca fluviatilis ) using ultrasonography

“…In the same way, since early 1980s, ultrasonography has been mainly used to determine the sex of numerous fish species, for conservation, research or aquaculture purposes. Among them, we can list coho salmon Oncorhynchus kisutch (Martin et al, 1983), Pacific herring Clupea pallasii (Bonar et al, 1989), Atlantic salmon Salmo salar (Mattson, 1991;Naeve et al, 2018), rainbow trout Oncorhynchus mykiss (Reimers et al, 1987), Atlantic halibut Hippoglossus hippoglossus (Martin-Robichaud & Rommens, 2001;Shields et al, 1993), striped bass Morone saxatilis (Blythe et al, 1994), Atlantic cod Gadus morhua (Karlsen & Holm, 1994;McEvoy et al, 2009), stellate sturgeon Acipenser stellatus (Moghim et al, 2002), shovelnose sturgeon Scaphirhynchus platorynchus (Colombo et al, 2004;Wildhaber et al, 2005), Murray cod Maccullochella peelii peelii (Newman et al, 2008), hapuku Polyprion oxygeneois (Kohn et al, 2013), European eel Anguilla Anguilla (Kucharczyk et al, 2016) or Chinese sturgeon Acipenser sinensis (Du et al, 2016).…”