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3.12.6 Deep-water Resources south of 63°N

These resources are assessed on a bi-annual basis and 2000 is clarified below in an answer to NEAFC and Coop. Res. Rep. 242 (2000) includes an overview of Norwegian requests for further information. these resources and their status. The advice given in

3.12.6.a Answer to Special Request on the Management of Deep-water Species

NEAFC requested ICES to consider the following with Use of life history parameter as a basis for regards to deep- species: management a) Characterize and classify the most important As noted above management should be based on deep-sea species (listed in Annex 2 in the population dynamic information. However, for deep- request) according to their life history strategies water species such data are largely lacking and much of and rank them by vulnerability to exploitation the scientific basis for management must therefore be together with more well known deep-sea species, taken from the general biology of the species. There is a e.g., redfish and Greenland halibut; well-developed theoretical framework on life history b) Clarify advice statements for stocks where little dynamics as a basis for scientific advice on exploitation. biological information is available in order to generate consistency in advice (as outlined in ICES has used life history parameters to rank the Annex I pt 1-3 of the request); species according to which, according to c) Give established reference points used as basis the theoretical framework should be informative guides for statements on stock status (as outlined in on vulnerability to exploitation: Annex I pt 5 in the request); and d) Provide advice on how to improve data- S For a given mortality, stocks of lower collecting systems and advice on appropriate productivity will decrease faster than more improvement for monitoring deep-sea resources productive stocks. (as outlined in Annex I pt 6 of the request). S Norway requested ICES: Once depleted, the more productive species will be able to rebuild more quickly. To evaluate the present assessment approach of treating different species of deep-water sea Vulnerability includes many factors in addition to resources as one unit. species life history. Some factors are biological, e.g. aspects of species biology like shoaling, migrations, habitat preferences, whereas others reflect the fisheries, This is essentially the same request as a) above. e.g., markets for the species and fleet capacity. Many Answers to the two requests are therefore combined in deep-water species are widely distributed, and features this section of the ICES advice on management. of their life history may not be constant across their range or may change in response to exploitation. For Answer to point a) of the NEAFC request and to these reasons life history parameters are useful, but not Norway perfect guides to sustainable management. However, because the most and best information is available on ICES considers that evaluation of stock status on each life histories they are the primary guide at this time. species should be done based on the population dynamics of that specific species and that all deep-water Below, deep-water species are ranked by their life species should not be treated as having the same history parameters, which are indicators of productivity. population dynamics. ICES has in its advice assessed As noted above this means that those stocks ranked as the stocks individually based on available data. The more vulnerable will be those stocks for which ranking requested by NEAFC further enlightens the detrimental impacts of fishing will be more difficult to differences in population dynamics among deep-water reverse. species.

ICES Cooperative Research Report No. 246 625 Ranking the deep-water species according to life the lowest fraction of the virgin . Less history parameters vulnerable species were assigned higher ranks. Where the biological parameters were considered to be quite Annex II of the NEAFC lists the following species: similar between two or more species the same rank was assigned. The available data did not allow ranking of all species (or species groups) according to all parameters. Common Name Scientific Name The species with no data are listed at the top of the Blue ling Molva dypterygia tables and given no rank (as indicated by “?”). Some Ling Molva molva parameters may be highly correlated. For example, Tusk Brosme brosme longevity, growth rate and natural mortality are most Roundnose grenadier Coryphaenoides often derived from the same data, or they may rely upon rupestris the same, unverified, assumptions. It is then to be Aphanopus carbo expected that these different parameters provide the Greater silver smelt Argentina silus same species ranking. Hoplostethus atlanticus Red sea bream Pagellus The estimated life history parameters used to rank the bogaraveo species are taken from the literature. Numbers given Greater forkbeard Phycis blennoides may have been estimated by different methodologies, Alfonsinos Beryx spp. have wide confidence intervals, or apply to local areas or environments. Where data are available from the ICES areas they were preferred. When no information was available information was extrapolated from other Available information on life history characteristics was areas. Parameter estimates from the Mediterranean, compiled, and the deep-water species were ranked where at least growth is clearly different, were not together with three reference species; redfish (Sebastes included in the analyses. marinus and S. mentella) and Greenland halibut (Reinhardtius hippoglossoides). The three reference In order to summarise the detailed information, a simple species have been exploited for an extensive period rank average was produced and the species (or species within the ICES area, and more data on their biology groups) were ordered (Table 3.12.6.a.1). This analysis is and population dynamics are available than for other of course crude. It should be emphasised that the deep-water species. The ranking was made on the basis underlying data are of variable quality and that new of several biological parameters: longevity, growth, information is needed for several species in order to natural mortality, fecundity, and length or age at first achieve a more reliable ranking. Nonetheless, the main maturity (Tables 3.12.6.a.2-6). Rank 1 is assigned to the pattern as indicated is believed to be robust. species for which the sustainable catch level should be

626 ICES Cooperative Research Report No. 246 Table 3.12.6.a.1 Summary of ranking of the deep-water species and the reference species redfish and Greenland halibut. A low rank means high vulnerability. Cases where no rank could be assigned due to lack of information are indicated by “?”. The overall rank in the rightmost column is an average of the available ranks in each row. Life history parameter Rank average

Species Longevity Growth Natural Fecundity Length (? rate Mortality and age at ignored) first maturity Greater Forkbeard 4 ? ? ? ? ? Deep water squalid : Centroscymnus 2 ? 1 1 2 1.5 coelolepis Centrophorus squamosus

Orange roughy 1 1 1 4 1 1.6

Roundnose grenadier 2 3 2 3 2 2.4 Sebastes 3 2 2 4 2 2.6 Greenland halibut 4 3 3 3 3 3.2

Greater silver smelt 3 5 ? 2 3 3.3 Tusk 4 ? 2 6 3 3.8

Black scabbardfish 4 6 3 ? 3 4.0 Blue ling 3 ? ? 5 4 4.0 Ling 4 ? 3 5 4 4.0 Red (Blackspot) Seabream 4 4 ? 4 5 4.3 Beryx decadactylus 5 4 ? ? 5 4.7

Beryx splendens 5 5 ? ? 5 5.0

ICES Cooperative Research Report No. 246 627 Longevity and Swan, 1996; Mace et al., 1990). For orange roughy and Sebastes, radiometric dating of cores has Estimates of longevity are based upon maximum age been carried out, and the results suggest longevity in observed from otolith readings (Table 3.12.6.a.2). For accordance with otolith growth zone readings (Fenton et several species age is difficult to determine and age al., 1991; Francis 1995; Kastelle et al., 2000; Smith et readings may not be validated. Although some al., 1995). validations have been attempted, satisfactory validations in the sense of Beamish and McFarlane (1983) are only Orange roughy, roundnose grenadier, and the deep- available for few deep-water species. For orange roughy water squalids have the longest life-spans. Most of the and roundnose grenadier, age validation has been other species have intermediate longevity (15-30 yrs), carried out, but results apply only to juveniles (Gordon but the Beryx species are relatively short-lived.

Table 3.12.6.a.2 Deep-water species ranked according to longevity. Rank Species Longevity (years) Authors 1 Orange roughy 125 Annala and Sullivan, 1996; Tracey and Horn, 1999 2 Roundnose grenadier >60 Allain and Lorance, 2000; Bergstad, 1990; Kelly et al., 1997 2 Deep water squalid sharks Centroscymnus coelolepis - Centrophorus squamosus 60-70 Clarke, in press, and WD 3 Sebastes 45-50 Nedreaas, 1990

3 Blue ling ~30 Bergstad and Hareide 1996; Magnusson et al. 1997 3 Greater silver smelt ~35 Bergstad, 1993 4 Greenland halibut 15-20 ICES Arctic Fisheries WG

4 Ling ~20 Bergstad and Hareide 1996; Magnusson et al. 1997 4 Tusk ~20 (?) Bergstad and Hareide 1997; Magnusson et al. 1997 4 Black scabbardfish 8 Morales-Nin et al., 1996 12 from whole FAIR 1999; BASBLACK 2000 ~25 from sections 4 Red (Blackspot) Seabream 16 Menezes et al., 2001 4 Greater Forkbeard 15 ? FAIR 1999, Sub-t. 5.12, Doc.55 5 Beryx decadactylus 13 Krug et al.,1998 5 Beryx Splendens 11 Krug et al.,1998

Growth rate fit properly the same set of length-at-age data, especially when the full age range of the population is The k parameter of the von Bertalanffy growth equation not represented in the sample. This may for example be is used here as an expression of growth rate and species a great problem for black scabbardfish for which both with the lowest ranks have the lowest growth parameter juveniles and adults are lacking in samples from the (Table 3.12.6.a.3). This coefficient represents the rate at west of the British Isles and off Portugal (only sub- which the individuals of a species reach their asymptotic adults (a "sub-adult" is a juvenile, but a rather large juvenile approaching maturity) are caught). Ripe length, while L∞ is a measure of asymptotic size (Francis, 1996). However, these two parameters are specimens have only been found near Madeira and the Azores. highly correlated and strongly different. L∞,k pairs may

628 ICES Cooperative Research Report No. 246 Table 3.12.6.a.3 Deep-water species ranked according to growth rate. Rank Species Growth rate, k (y-1) Authors/comments ? Ling Probably Rank 3 ? Blue ling Probably Rank 3 ? Tusk Probably Rank 2 ? Greater Fork beard ? Centroscymnus coelolepis Centrophorus squamosus 1 Orange roughy 0.06-0.07 Annala and Sullivan, 1996; Tracey and Horn, 1999 2 Sebastes 0.06-0.11 Nedreaas, 1990 3 Roundnose grenadier ♂ 0.105 Bergstad, 1990 ♀ 0.100 ♂ 0.128 Kelly et al., 1997 ♀ 0.101 Allain and Lorance, 2000 ♂ 0.06 ♀ 0.06 3 Greenland halibut 0.02-0.03 (probably Bowering and Nedreaas 2001 underestimated) (growth curves linear) 4 Red (Blackspot) Seabream Menezes et al., 2001 ♂ 0.17 ♀ 0.102 4 Beryx decadactylus Menezes et al., 2001 ♂ 0.11 ♀ 0.165 5 Greater silver smelt Bergstad, 1993 ♂ 0.20 ♀ 0.17 5 Beryx splendens Menezes et al., 2001 ♂ 0.134 ♀ 0.141 6 Black scabbard fish 0.251 Morales-Nin et al., 1996

Based on the growth data, orange roughy is again the Natural mortality species with the lowest rank. Black scabbardfish appears to be much faster growing. The estimated k is Estimates of the natural mortality of deep-water species based upon the age reading from Morales-Nin and Sena- were derived either from catch curves of unexploited Carvalho (1996), however, the ages estimated from stocks (roundnose grenadier, tusk) or from crude sectioned otoliths, e.g., as used by Connolly and Kelly estimates according to the maximum age observed in (FAIR 1999), would provide a much lower k parameter. the populations (Annala and Sullivan, 1996; Anon. The results from the recently finished BASBLACK 2000a). Such data were only available for a few species project suggest that growth rate is rather high (see WD (Table 3.12.6.a.4). by Figueiredo et al. 2001).

ICES Cooperative Research Report No. 246 629 Table 3.12.6.a.4 Deep-water species ranked according to natural mortality rate. Rank Species Natural mortality, M (y-1) Authors/comments ? Blue ling ? Greater silver smelt ? Red (Blackspot) Seabream ? Greater forkbeard ? Centroscymnus coelolepis Centrophorus squamosus ? Alfonsino (Beryx spp.) 1 Orange roughy 0.04 – 0.045 Annala and Sullivan, 1996; Tracey and Horn, 1999 2 Sebastes 0.1 ICES Arctic Fisheries WG

2 Roundnose grenadier 0.1 Lorance et al., in press 2 Tusk 0.1-0.2 Anon. 2000a 3 Greenland halibut 0.15 Value used by ICES WGs

3 Black scabbard fish 0.17 Martins et al., 1989 3 Ling 0.2-0.3 Derived from Z estimates compiled by SGDEEP 2000.

Fecundity and reproductive processes species. There is probably a potential for compensation to exploitation, but the actual potential may be very Deep-water species are adapted to an environment limited. The fecundity of orange roughy may increase as where disturbance may be weaker or more rare than in the stock reduces (Koslow, et al., 1995), however this the more shallow water . Life history theory may not be the case for all stocks (Clark, et al., 2000). predicts several features of their reproductive biology. The scope for compensation would seem very limited Deep-water species may have developed a reduced for the deep-water squalids. fecundity balanced by a much higher survival of adult fish. For the long-lived species, the total egg production Within , there should be a major difference of an adult may be spread over a long period and this between species that have a short spawning period, such may be necessary to ensure sufficient recruitment. as the orange roughy, and species that all year Reduction of the adult biomass by fishing may thus round or during most of the year (e.g. roundnose have a stronger negative effect on the deep-living grenadier west of Britain, greater argentine in the than for species living on the shelf. Data on fecundity Skagerrak). The survival rate of eggs, larvae and early are still limited (Table 3.12.6.a.5), as is exact juveniles would be expected to be different for species information on reproductive strategies in general. There for which a short spawning period is finely tuned to may also be geographical variations. E. g. the roundnose some expectedly "optimal" survival conditions for the grenadier to the west of Britain appears to spawn at least spawned eggs, and for species whose progeny is 2 batches per year (Allain, 1998, 1999, in press) and the dispersed more widely in space and time. This leads to a spawning period may be protracted. However, in the "success of " parameter. This is very poorly Skagerrak, the same species appears to have a single known for deep-water species. However, for the orange well-defined late autumn spawning period (Bergstad roughy, the recruitment seems to be episodic (Clark, and Gordon, 1994). 1998; Clark, et al., 2000; Koslow, et al., 2000). It could be argued that the recruitment of species that spawn all The estimate of fecundity may have a very different year round should be less variable as it is more likely meaning in terms of resilience to exploitation and/or that a more constant proportion of the progeny capacity of recovery, depending on the early life history encounters favourable conditions, while for the orange and dispersion processes of larvae. Early life history roughy the conditions are either good or bad for all of a processes are generally poorly known for deep-water given year class of one population.

630 ICES Cooperative Research Report No. 246 Table 3.12.6.a.5 Deep-water species ranked according to fecundity. Rank Species Fecundity Authors Total (N..y-1) relative(N. kg-1.y-1) ? Black scabbard fish ? Greater forkbeard ? Alfonsino 1 Deep water squalid sharks Centroscymnus coelolepis 7 – 11 (3) 1 or 2 (5) Girard and Du Buit, 1999; Girard, 2000) 13 Clarke, WD

Centrophorus squamosus 8 – 19 (4) 1 or 2 (5) Girard and Du Buit, 1999; Girard, 2000 8 Clarke, WD 2 Greater silver smelt Few thousand 3 Greenland halibut 20 000-70 000 Gundersen et al. 1999 3 Roundnose grenadier (2) 23 000 25 000 Allain, 1998, 1999, (2 500 – 70 000) in press 4 Red (Blackspot) Sea Bream 290000-1125000 Krug, 1998 4 Orange roughy (1) 28 000 – 385 000 38 000 Berrehar, DuBuit, (11 000 – 136 000) Lorance, unpublished 4 Sebastes mentella 30 000 – 40 000 40 000 Shibanov V. per. Comm. (Irminger Sea) 5 Ling Millions 5 Blue ling Millions 6 Tusk Millions

(1) Data for the North-east Atlantic; values from the assumed rather than validated age data. It is difficult to southern hemisphere are lower due to the smaller rank the species according to these criteria. The size of the fish. parameter of interest is not the length or age per se, rather at what stage in their life they start to reproduce. (2) per batch. A better basis for the ranking would have been (3) Ovarian fecundity: number of simultaneous ovules age/length at first maturity as a proportion of an in the ovaries. estimate of maximum age/length. A precise proportion could not be derived for all species, but an approximate (4) Uterine fecundity: number of simultaneous measure was used whenever possible as basis for the embryos in the uterus. final ranking given in Table 3.12.6.a.6. (5) Hypothetical mean number of pup/year/female estimated from the ovarian or uterine fecundity, Data from Australia and New Zealand suggest that and duration of the reproductive cycle derived orange roughy matures at a very high age (25-30 yrs), from indirect method. but this is not really late in life for a species with a life span of 100 years or more. Others may spawn for the Length and age at first maturity first time at an age corresponding to a half or a third of their maximum life-span.The lings and tusk grow to Length at first maturity is known for many species about half their maximum size before maturing, but (Table 3.12.6.a.6). Age at first maturity is less often others such as roundnose grenadier and greater silver determined, and the estimates frequently depend on smelt are comparatively big when spawning for the first time.

ICES Cooperative Research Report No. 246 631 Table 3.12.6.a.6 Deep-water species ranked according to length and age at first maturity. Rank Species Length at first Age at first maturity Authors maturity (cm) (years) ? Greater Forkbeard 1 Orange roughy (1) Berrehar, Du Buit, Lorance, ♂ 48 unpublished ♀ 52 2 Sebastes 12-15 ICES Arctic Fisheries WG 2 Roundnose grenadier (2) Bergstad, 1990 ♂ 8 ♀ 10 ♂ 13.3 (PAFL) Allain, 1998, 1999, in press; FAIR, ♀ 14.2 (PAFL) 1999, Iceland 2 Centroscymnus coelolepis ♂ 86 Girard and Du Buit, 1999; Girard, ♀ 102 2000; Centrophorus squamosus Clarke WD ♂ 98-101 Girard and Du Buit, 1999; Girard, ♀ 124-128 2000; Clarke WD

3 Greenland halibut ♂ 40 4 Høines, pers. comm. ♀ 60 8 3 Tusk 40-45 8-10 Magnusson et al. 1997 3 Greater silver smelt Magnusson 1988; Bergstad 1993; ♂ 36.2 6-9 FAIR, 1999 ♀ 37.2 6-9 3 Black scabbard fish ♂ 84-88 FAIR 1999, Iceland ♀ 92-97 Sena-Carvalho, Reis, Morales-Nin, ♂ 73.7 in prep, in Anon., 2000a ♀ 102.7

4 Ling 60-75 5-7 Magnusson et al. 1997 4 Blue ling ♂ 73.9 FAIR 1999, Iceland ♀ 89.0 5 Red (Blackspot) Seabream 30-35 cm Spain,WD by Gil and Sobrino, 2001 ♂ 26.2 3 Azores, Mendonca et al., 1998 ♀ 29.2 4 5 Beryx splendens ♂ 22.9 2 Azores, Mendonca et al., 1998 ♀ 23 2 5 Beryx decadactylus ♂ 30.3 4 Azores, Mendonca et al., 1998 ♀ 32.5 4 (1)Data for the Northeast Atlantic, fish in the southern hemisphere mature younger at a lower size (Horn et al., 1998; Tracey and Horn, 1999).

632 ICES Cooperative Research Report No. 246 Answer to point b) of the NEAFC request - Roundnose grenadier is estimated to be depleted to 30% of unexploited stock size, and a Annex I of the NEAFC request reads as follows: 50% effort reduction is envisaged. In comparison, tusk is estimated to be more depleted (to 20% of unexploited stock size), yet Request for clarification of advice for deep-sea the advice is to reduce effort by only 30%. species

3. For ling, total mortality in the stock is estimated The following points are issues where review and to be 0.7 to 0.8 (implying an F of around 0.5 to clarification of advice on deep-sea species presented in 0.7) and advice is to reduce fishing effort by the June 2000 ACFM report are requested: 30%. This implies that acceptable fishing mortality levels are in the range about 0.4 to 0.5. 1. Two statements are made that are generally This is the same sort of range as proposed for applicable to deep-sea fisheries where there is more productive species on the , little biological information: and for which close monitoring of the stocks allows reduction of risk by taking appropriate "ICES recommends immediate reduction in remedial actions in the case of stock declines. these fisheries unless they can be shown to be Such options are not available in the case of sustainable" deep-sea species. Additionally, the stock is reported to be "outside safe biological limits in and some parts of its range" by ACFM. Given that, as advised on p. 265, "the species and stocks are a "Consistent with a precautionary approach, priori not able to cope with high or even fishing should not be allowed to expand moderate exploitation rates", the implied levels faster than the acquisition of information of risk for this stock seem much higher than necessary to provide a basis for sustainable those normally considered acceptable. exploitation." 4. ICES is asked to clarify, for black scabbardfish, Both statements appear on p. 186 of the ACFM to which zones the advice is intended to be June 2000 report, where a general recommendation applied. is made for many stocks. The second statement is also repeated in respect of argentine, orange 5. For several stocks, reference is made that the roughy, red seabream, greater forkbeard, and stock is "outside safe biological limits". alfonsinos. However, the precautionary reference points and the basis for their definition is not given in the The statements are contradictory. The former ACFM report, although mention is made of these states that catches should be reduced (but gives no in the corresponding Study Group report. As for indication by how much). The latter statement the other stocks, ICES is asked to state explicitly implies catches can be maintained at current levels. its precautionary reference points as the basis for This ambiguity in the advice should be resolved. defining safe biological limits, and to describe the risks incurred on violating such limits. 2. Comparing different stocks, there does not seem to be consistency between the estimated level of 6. ACFM recommends that "a comprehensive data stock depletion and the level of the proposed collection system is urgently required, and reductions. Specifically, research on all stocks should be increased to provide the data necessary for assessment". It would be helpful if ACFM would review the - Orange roughy is estimated as being outside existing and proposed data-collection systems safe biological limits and biomass is estimated as and advise on extensions or modifications that being about half Bmsy in Sub-area VI. This is a may be required to make them appropriate for similar situation to that estimated for black monitoring deep-sea resources. Specifically, scabbardfish, tusk and roundnose grenadier, but STECF in 2000 has recommended minimum whereas in those cases an effort reduction of 30 standards of data collection for many stocks, to 50% is advised, for the orange roughy the including deep-sea species; and NEAFC has had advice only implies that catches should not a log-book reporting scheme in existence for increase. The advice seems to be on a different some years (see EU regulation 2807/83). level of risk acceptance than ICES has accepted for many other species.

ICES Cooperative Research Report No. 246 633 Answer to the NEAFC request point b) new gears or fleets) should be permitted only when these fisheries expand very slowly, and are Clarification of advice statements, Annex I, Pts. 1-4. accompanied by programmes to collect data which allow evaluation of stock status. Species for which this type of advice is applicable is listed under Category 1 in Pt. 1 Apparent contradictory statements Table 3.12.6.a.7. The sentence “Consistent with a precautionary Most exploited deep-water species are at present approach, fishing should not be allowed to expand faster considered to be harvested outside safe biological limits. than the acquisition of information necessary to provide ICES recommends immediate reduction in these a basis for sustainable exploitation” only applies to deep fisheries unless they can be shown to be sustainable. water fisheries that may develop on virgin stocks When these fisheries have been reduced, consistent with (stocks that have not previously been exploited) or on a precautionary approach, fishing should not be allowed stocks where exploitation clearly has only been on a to expand faster than the acquisition of information marginal or limited part of the entire population. New necessary to provide a basis for sustainable exploitation. fisheries, expansion into unexploited areas, or Species/stocks for which this type of advice applies is significant changes in the fisheries (i.e. introduction of listed under Category 2 in Table 3.12.6.a.7.

634 ICES Cooperative Research Report No. 246 Table 3.12.6.a.7 Species/stock grouped according to which advice statement applies. Category 1 comprises stocks for which new fisheries may develop, but only if the state of the stock is closely monitored. Category 2 comprises stocks that are fully exploited or overexploited and for which immediate reduction in the fishery is recommended. * indicates that all known stocks of the species falls in that category. Mainly based on ICES Coop. Res. Rep. No. 242, including some new evaluations of expanding fisheries. Species/Stock Category 1 Category 2 Comment Developing new fisheries Fully or overexploited General Advice 2000: Advice 2000: recommendation Fisheries on such species be Immediate reduction unless fisheries permitted only when they can be shown to be sustainable expand very slowly, and are accompanied by programs to collect data which allow evaluation of stock status Blue ling All Populations

Advice 2000: there should be no directed fisheries for this stock and measures should be implemented to reduce/minimise catches of this stock in mixed fisheries. Ling All Populations

Advice 2000: overall fishing effort should be reduced by 30%. Tusk Hatton Bank fishery (Part of All areas except Hatton Bank Mainly by-catch in Sub-area VI and XII) ling fishery. Advice 2000: overall fishing effort should be reduced by 30%. Roundnose Stocks outside Sub-areas VI, Sub-areas VI, VII and Vb combined Status of fishery and grenadier VII, Vb stock in the Advice 2000: Skagerrak (IIIa) reduction in fishing effort by 50% for unclear but landings Sub-areas VI and VII and Division Vb are high compared combined. with size of area. Black Stock in Sub-area X Stock in Sub-areas V, VI, VII, and XII Stock structure scabbardfish Stock in Sub-area IX is probably remains unclear. Category 2.

Advice 2000: Reduction in fishing effort by 50%. Greater silver All Populations Applies primarily to smelt or areas where target argentine fishery is expanding, e.g. V, VI, VII Orange roughy Stocks in all areas except VI Sub-area VI Stock structure and status unclear except Advice (see pt 2 below): in Sub-area VI a significant reduction of effort to around 50%. Red All Populations (=blackspot) seabream Greater All Populations State of stocks forkbeard unknown Alfonsinos All Populations State of stocks (Beryx spp.) unknown Deep-water All Populations State of stocks squalid sharks unknown

ICES Cooperative Research Report No. 246 635

Pt. 2 Inconsistencies in advice. Comparisons between The advice on tusk was not based on an estimate of the stocks. overall biomass to be below 20% of the virgin stock biomass. Tusk is estimated to below Ulim (20% of virgin The analysis presented in the answer to the NEAFC biomass) in Division Vb only. Elsewhere CPUE has request a) suggests that the three species mentioned in been declining, but data since 1996 are not available for the NEAFC request, i.e. Orange roughy (average rank some of the most important fisheries. There is not 1.6), Tusk (average rank 3.8) and Roundnose grenadier sufficient reliable data to evaluate stock status in these (average rank 2.4), differ in their vulnerability to areas, but the fisheries have continued in the same fishing. manner and may even have expanded since 1996. ICES therefore judged that an overall significant reduction in effort is required and proposed a 30% reduction. Orange roughy is vulnerable to fishing both because of its life history (see answer to request a)) and because it is an aggregating species. Catch per unit of effort data Compared with data available for tusk, data for may be a poor indicator of impact of harvesting because roundnose cover a much wider area the index may stay high despite sequential depletion of (Division Vb and Sub-areas VI and VII). The local aggregations. The vulnerability of orange roughy assessment is therefore considered more reliable than was not fully reflected in last year’s advice. An that of tusk, but the grenadier is more vulnerable to assessment of the orange roughy in Sub-area VI is fishing than the tusk. The biomass estimate for available, while the stock status in other Sub-areas roundnose grenadier is close to Ulim. Compared with cannot be assessed due to insufficient data. No new tusk, and despite the stronger confidence in the evaluation of the orange roughy in Sub-area VI is grenadier assessment, a stronger reduction in effort is available this year, but on the basis of the 2000 advisable for grenadier, mainly because of the assessment showing a very depleted stock, a significant differences in vulnerability between the two species. reduction of effort to around 50% is proposed. The This was the basis for the advice on a 50% reduction in fishery in Sub-area VI is more intensive than in other effort. Sub-areas. The reduction of effort proposed is similar to that proposed for the somewhat less vulnerable but heavily exploited roundnose grenadier.

636 ICES Cooperative Research Report No. 246 Pt. 3 Ling - Acceptable mortality level First, any specific negative change in stock status will be more serious for deep-water species than for shelf Ling has a wide geographical and bathymetrical range stocks, and more difficult to reverse. As described in also comprising shelf and coastal waters. Ling has life the answer to the NEAFC request pt 1, see above, the history characteristics and that makes it less life histories of deep-water species mean that they are vulnerable to exploitation than the more long-lived less productive than shelf stocks. Being less deep-sea species such as orange roughy, Sebastes a.o. productive, they can sustain only lower exploitation The available biological parameters suggest that rates, and they can only increase more slowly in exploitation limits might be comparable to, e.g., response to management actions intended to improve Northeast Arctic . Such stocks seem by experience stock status. to be able to sustain fishing mortalities around 0.4. This is the background for the 2000 advice" that the Second, for several reasons uncertainty will be higher overall fishing effort be reduced by 30%." for deep-water stocks. Data are sparse for deep-water species in the ICES area, and even with expanded Pt. 4 Black Scabbardfish - Zones to which the ICES research and monitoring efforts, will remain less advice applies complete than data for shelf stocks for many years to come. Moreover, the types of information available for these species are rarely the time-series of age- The data available cover the black scabbardfish in Sub- structured catch and survey data, which form the basis areas V, VI, VII and XII. However, there is also a for assessments of shelf stocks. Therefore advice and fishery on black scabbardfish in Sub-area IX. ICES management will have to be based on indicators of will include this component in the overall advice for stock status other than B and F, and the performance of management of the black scabbardfish until evidence these indicators as guides to advice and management is that Sub-area IX supports a single stock separate from poorly known. Also, because of the differences in life that in other areas becomes available. Therefore the histories between deep-water and shelf species, advice for a reduction in fishing effort by 50% applies knowledge of perturbations of population status to the Sub-areas V, VI, VII, XII and IX. (reductions in abundance, changes in age composition, etc.) from which shelf species can recover cannot be A new fishery for black scabbardfish in Sub-area X is transferred with confidence to deep-water species. developing. The catch rates obtained are very high compared with other longline fisheries for this species. Reference points for deep-water species must be set in This suggests that abundance in this Sub-area is much context of both of those factors. Because any harm will higher than in other sub-areas. There is insufficient be more serious and more difficult to reverse for deep- data available for a proper analysis of the stock water stocks than for shelf stocks, limit reference point situation. It is proposed that the fishery is allowed to of deep-water species must be set to ensure that stocks develop following the principle specified for a new are in better condition than the stock status associated deep-water fishery as discussed under the answer to with limit reference points for shelf stocks. Because point 1) above. The fishery in Sub-area X is developing uncertainty is greater for deep-water stocks, under close monitoring by observers collecting relevant precautionary reference points will have to be further data following this advice. from limit reference points than is the case for shelf stocks, to achieve the same degree of risk avoidance by Answer to NEAFC request point c): Give management. established reference points used as basis for statements on stock status (as outlined in Annex 1 of ICES used biological reference points for deep-water the request pt 5). species for the first time in 1998 and suggested using the following limit and PA reference points: The Precautionary Approach gives two strong justifications for advice on and management of deep- F = F water species being more conservative than for the lim 35%SPR F = M shelf stocks, which have been the historic focus of pa fisheries. Specifically, the Precautionary Approach requires that decisions be risk averse when there is risk Blim = 0.2*Bmax (maximum observed biomass, may be a of harm that is serious or difficult to reverse, and that smoothed (over time) estimate) management should be more cautious when uncertainty is greater. The discussion below addresses these Bpa = 0.5*Bmax justifications in the general case for deep-water species. Deep-water (and shelf species) show diverse For many stocks there is no absolute biomass estimate life histories, so there may be occasional exceptions to available and instead ICES uses indicators, e.g. a each argument, and advice and management should CPUE index from a research vessel survey (preferably) always be based on the best information available. or from logbook data for . These indices are notated U so that Ulim is an index for Blim,

ICES Cooperative Research Report No. 246 637 etc. Using such indices posed for data poor situations NEAFC issued in 1998 “Recommendation on a scheme the references points become: of control and enforcement in respect of fishing vessels fishing in areas beyond the limits of national fisheries jurisdiction in the convention area (“The scheme”). Ulim = 0.2*Umax (maximum observed biomass indicator, may be a smoothed (over time) index) This scheme was entered into force on 1 July 1999. The EU has implemented corresponding reporting practices for their own and non-EU vessels fishing U = 0.5*U pa max within its EEZ. For most deep-water stocks the only information Articles 7 and 8 of the NEAFC scheme concerning available on fishing mortality rates is from catch- logbooks and reporting of catch and effort are those curves (if an estimate of M is available) and, given that most relevant to the ICES work on deep-sea resources. the assessment methods used (Production and modified ICES has attempted to identify desired changes with DeLury models) generate estimates of current and the view to facilitate the improvement of basic virgin exploitable biomass, these biomass reference information and data flow to the assessment process. points were used for all stocks.

Spatial Information ICES advice on deep-water species in 2000 did not refer explicitly to reference points for the individual In accordance with Article 7b (and Annex IV), stocks. However, Ulim = 0.2*Umax and Upa = 0.5*Umax, were adopted for all the deep-water species for which logbooks shall contain species-specific catch and effort advice was provided, although further work is needed information on the spatial scale of ‘small statistical to determine if deep-sea species can recover readily rectangle or fishing location’. from depletion to 20% of the unexploited condition. As knowledge accumulates on deep-water species and The fishery for deep-water species are under VMS fisheries, ICES will continue to bring forward and satellite tracking, a system that provides very detailed refine reference points for these stocks. ICES will information on the position of the vessel. Such detailed assess the status of the deep-water species again in data will be subject to confidentiality considerations, 2002. but it may be an efficient solution to the statistics problem to link the logbook databases with the VMS Answer to NEAFC Request point d). Provide advice databases with a time lack. From a stock assessment on how to improve data-collecting systems and point of view such a time lag of between 3 and 6 advice on appropriate improvement for monitoring months would be acceptable. deep-sea resources. However, such detailed statistics have not consistently Assessments of deep-water species depend on been available. Usually data only allow an aggregate retrospective time-series of catch and effort. Currently catch and effort estimate on the scale of ICES Sub-area used time-series are referenced to ICES Sub-areas and or Division, and this system of areas is not suitable for Divisions or aggregates of these. Because of the patchy deep-sea fish stocks. It would therefore be of great distribution of deep-water fish interpretation of such value to the assessments if data on the requested finer- time-series depends on knowledge of the fishing scale data were made available. This would enable grounds where these catches were taken. Therefore, aggregation of catches by more natural sub-areas. It is detailed spatial information on catch and effort is therefore suggested that catch and effort data by important. Landings and effort data on more relevant statistical rectangle be provided to ICES. reporting areas, such as rectangles would be of special importance for fisheries statistics for Sub-area XII. ICES should cooperate with NEAFC and together explore the possibility of compiling a database from ICES finds that the existing data could be improved by: which time-series of data by statistical rectangles can be constructed. S Providing more detail on spatial information on where the fishing took place. Many deep- Depth on Fishing Ground sea species extend their occurrence over very wide areas, but with very uneven distribution Logbooks used in deep-water fisheries do not include within these areas. Information on a fine scale information on depth of fishing, although fishing would be of great value to the assessments. operations may extend over wide depth ranges within short time-periods. The lack of provision for the S Including the depth of the fishing ground in recording of depth is a shortcoming in the scheme. the logbook. Even within a statistical rectangle the depth may vary considerably, and it is known from several previous studies that target species and communities change S Expanding the species list to include request markedly with depth. Inclusion of depth information, for information on sharks and rays. even coarse data such as an average depth of tows or

638 ICES Cooperative Research Report No. 246 longline sets, would therefore facilitate more detailed Gil, J. and Sobrino, I. 2001. New biological data analysis. information about the red seabream (Pagellus bogaraveo) of the Strait of Gibraltar (ICES If VMS data were linked to the logbook databases it IXa). would be possible to infer the fishing depth using Sigurdsson, T. 2001. Information on the fishing charts and an entry in the logbook would not be species in Icelandic waters. necessary. Vinnichenko, V. I. and Khlivnoy, V. N. 2001. Russian deep-sea investigations and fisheries in the Species List Northeast Atlantic in 2000. 19p. Attachment II related to Article 8 lists the species included in the scheme. For most species this list is REFERENCES adequate, but a problem is the lack of species-specific information for sharks and rays. Deep-sea sharks have Allain V., 1998. Reproduction and fecundity of 3 life histories that make them particularly vulnerable to species of deep-sea fish from the North-east enhanced mortality rates, and life history patterns vary Atlantic Ocean. ICES C.M. 1998/O:4. among species. ICES has obtained some species- Allain V., 1999. Ecologie, biologie et exploitation des specific landings and effort data through national populations de poissons profonds de sampling schemes, but the data sets are limited and do l'Atlantique du nord-est., Océanologie not cover a sufficient proportion of the catch. Provision Biologique, Université de Bretagne Occidentale, of species-specific data on sharks and rays would Brest, 376. constitute a considerable improvement. Allain V., Lorance P., 2000. Age estimation and Sharks and rays are notorious difficult to identify and growth of some deep-sea fish from the therefore either an educational scheme among the Northeast Atlantic ocean. Cybium, 24 ((3) fishermen or an observer programme is required for a suppl.), 7-16. breakdown to species. Allain V., in press. Reproductive strategies of 3 deep- water benthopelagic fishes from the north-east Discards Atlantic Ocean. Fisheries Research, Annala J. H., Sullivan K. J., 1996. Report from the The recording of discards is optional (Annex IV). ICES Fishery assessment plenary, April-May 1996: has compiled discard information, mainly based on stock assessments and yield estimates. NIWA, observers reports, but again the scale of such Wellington,, 308 pp. observations is limited both geographically and temporally. The assessments would benefit from a Beamish R. J., McFarlane G. A., 1983. The forgotten change of the scheme whereby the recording of requirement for age validation in fisheries discards (by species) becomes mandatory. Experience biology. Transaction of the american fisheries suggests that reliable discard data can only be obtained society, 112 (6), 735-743. through an observer scheme. Bergstad O. A., 1990. Distribution, population structure, growth and reproduction of the Working Papers roundnose grenadier Coryphaenoides rupestris (Pisces: Macrouridae) in the deep waters of the Clarke, M. 2001. A Working Document for ICES Skagerrak. , 107, 25-39. Working Group on the Biology and Assessment Bergstad, O. A. 1993. Distribution, population of Deep Sea Fisheries Resources. 8p. structure, growth, and reproduction of the Durán Muñoz, P., 2001a. Results of a spring deep-sea greater silver smelt, Argentina silus (Pisces, exploratory fishing in North Atlantic in 2000. Argentinidae), of the Skagerrak and the north- 10 p. eastern North Sea. ICES Journal of Marine Science, 50:129-143. Durán Muñoz, P. 2001b. Preliminary available information on the Spanish deep-water bottom Bergstad, O.A. and Gordon, J.D. M. 1994. Deep-water trawl fishery on the Hatton Bank in 2000. 5 p. of the Skagerrak with special reference to Coryphanoides rupestris Figueiredo, I., Machado, P.B. and Moura, O. 2001. (Gunnerus, 1765 (Pisces, Macrouridae)) and Portugal mainland contribution to the 2001 Argentina silus. Sarsia, 79: 33-43. report of the ICES study group on the biology and assessment of deep-sea fisheries resources. Bergstad, O.A. and Hareide, N.-R. 1996. Ling, blue 8 p. ling and tusk of the North-east Atlantic. Fisken og Havet 15, 1996. 126 p.

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