Ovary resorption in the Norway lobster (Nephrops norvegicus) and its possible causes with special reference to sperm storage

Table 1 Conversion of the Agri-Food and Biosciences Institute (AFBI) and the Centre of Environment, Fisheries and Aquaculture Science (CEFAS) ovary staging scales into the revised staging scale as proposed by Becker et al. [5]

New scale	Description	AFBI scale	CEFAS scale	Conversion for comparative analysis
0	Immature ovary of juvenile female	1	1	0/1a
1a	Recovering ovary of adult female	1	1	0/1a
1b	Full resorption of ovary complete	–	1	–
2	Early ovary maturation	2	2	2
3	Intermediate ovary maturation	3	3	3/4
4	Advanced/late ovary maturation	4	3	3/4
5a	Partial resorption of spent ovary	–	–	–
5b	Full resorption without spawning	5	4	5b
Berried	Ovaries of berried females are staged	6	5 (with green eggs)	Berried
Berried	Ovaries of berried females are staged	6	6 (with brown eggs or remains)	Berried

This new scale differentiates between immature juvenile females (stage 0) on the one hand and adult females with recovering or earliest maturing ovaries on the other hand (stage 1a). It also discriminates between females with spent ovaries undergoing partial resorption (stage 5a) and females which failed to spawn and undergo full resorption (stages 5b–1b). To allow comparative analyses of the AFBI and CEFAS data, the stages assessed using their respective maturity scales were converted into a simplified scale adapted from Becker et al. [5]. The ovaries of berried females are neither staged by AFBI nor by CEFAS. Stage 5a, which only occurs in recently spawned females, is therefore not recognised in their data. The AFBI staging scale does also not recognize fully resorbed ovaries (stage 1b) as a separate stage. Stage 1b is assigned to stage 1 according to the maturity scale used by CEFAS

ISSN: 1438-3888