About this document
This is a prototype of an automatic report that documents how the user specified the operating model and their various justifications.
Introduction
Describe the history and current status of the fishery, including fleets, sectors, vessel types and practices/gear by vessel type, landing ports, economics/markets, whether targeted/bycatch, other stocks caught in the fishery. Esta especie se distribuye en aguas uruguayas y argentinas durante el verano y en invierno migra a la plataforma continental del sur de Brasil (Vooren, 1997). Como consecuencia de dicho comportamiento es capturada por distintas pesquerías artesanales e industriales de Argentina, Uruguay y sur de Brasil, las cuales afectan diferentes partes del stock durante su ciclo de vida (Miranda y Vooren, 2003; Oddone et al., 2005). En Argentina, la administración de las pesquerías de gatuzo se realiza a partir de dos unidades de manejo: la primera corresponde al área del Tratado y es administrada en conjunto por la CTMFM y la segunda, correspondiente a El Rincón está a cargo de la Autoridad de Aplicación pesquera argentina. Por su parte, la pesquería industrial de esta especie en Uruguay se encuentra bajo la administración de la CTMFM. El gatuzo (Mustelus schmitti), pez ángel (Squatina spp) y rayas (familia Rajidae) son los condrictios más explotados en el área del Tratado del Río de la Plata y su Frente Marítimo (en adelante área del Tratado). Son capturados por la flota industrial argentina principalmente como parte de la pesquería demersal multiespecífica conocida como “variado costero”. En el área del Tratado, a profundidades mayores de 50 m los condrictios más explotados son las rayas, capturadas principalmente por la flota argentina dirigida a merluza común (Merluccius hubbsi) (Grupo de trabajo condritios 2015, p47). A partir del 2010 se solicitó al Grupo de Trabajo Condrictios que se prioricen los estudios tendientes a aplicar modelos de evaluación que permitan estimar una aproximación a la captura total permisible (CTP) en el ámbito del área del Tratado del Río de la Plata y su Frente Marítimo (Aubone et al., 2011; Cueto, 2012, Cueto et al., 2013; Cueto et al., 2014) (see Grupo de trabajo condrictios 2015, p71). El gatuzo (Mustelus schmitti), junto con el pez ángel (Squatina guggenheim) y las rayas (familia Rajidae) son los condrictios más explotados en el área del Tratado del Río de la Plata y su Frente Marítimo (en adelante área del Tratado). Desde la costa hasta la isobata de 50 m son capturados principalmente por la flota industrial argentina como parte de la pesquería demersal multiespecífica conocida como “variado costero” y por la flota uruguaya (Categoría B) (Fig. 4). A profundidades mayores a los 50 m, los condrictios más explotados son las rayas, capturadas principalmente por las flotas de ambos países dirigidas a merluza común (Merluccius hubbsi). La pesquería argentina de gatuzo registra desembarques importantes la década de 1960 (>8.000 t), superando en 1973 las 9.000 y alcanzando en 1988 un pico de 13.500 t. Entre 1992 y 1999 los desembarques totales argentinos, que incluyen capturas realizadas en la ZCP, áreas costeras adyacentes y ZEE al sur de 39°S alcanzaron valores muy próximos o superaron las 10.000 t.
Describe the stock’s ecosystem functions, dependencies, and habitat types. El gatuzo (Mustelus schmitti) es el tiburón más desembarcado en puertos argentinos. Esta especie se distribuye en aguas uruguayas y argentinas durante el verano y en invierno migra a la plataforma continental del sur de Brasil (Vooren, 1997). Como consecuencia de dicho comportamiento es capturada por distintas pesquerías artesanales e industriales de Argentina, Uruguay y sur de Brasil, las cuales afectan diferentes partes del stock durante su ciclo de vida (Miranda y Vooren, 2003; Oddone et al., 2005). (ficha gatuzo, p1)
Provide all relevant reference materials, such as assessments, research, and other analysis.
Fishery Characteristics
Longevity
| Answered |
|---|
| Very short-lived (5 < maximum age < 7) |
| Short-lived (7 < maximum age < 10) |
| Moderate life span (10 < maximum age < 20) |
| Moderately long-lived (20 < maximum age < 40) |
| Long-lived (40 < maximum age < 80) |
| Very long-lived (80 < maximum age < 160) |
| Justification |
|---|
| M estimates from different methods: 0.165-0.320. age-specific: 0.139-0.404 (Ficha-gatuzo, p2). Ages determined from vertebral band counts ranged from 0 to 11 years. Calculated longevity and total natural mortality rates were 20.87 years and 0.19/year for females and 12.24 years and 0.26/year for males, respectively (Molina et al 2017) |
Stock depletion
| Answered |
|---|
| Crashed (D < 0.05) |
| Very depleted (0.05 < D < 0.1) |
| Depleted (0.1 < D < 0.15) |
| Moderately depleted (0.15 < D < 0.3) |
| Healthy (0.3 < D < 0.5) |
| Underexploited (0.5 < D) |
| Justification |
|---|
| stock assessment using a Bayesian Schaefer model. See Table 4 and 5 (Ficha gatuzo, p10). B2017/K =0.29 (0.23-0.46) |
Resilence
| Answered |
|---|
| Not resilient (steepness < 0.3) |
| Low resilience (0.3 < steepness < 0.5) |
| Moderate resilence (0.5 < steepness < 0.7) |
| Resilient (0.7 < steepness < 0.9) |
| Very Resilient (0.9 < steepness) |
| Justification |
|---|
| Gatuzo 1 to 13 (more common 4) sharks per female (Ficha-gatuzo, p3), related with fish size. |
Historical effort pattern
| Answered |
|---|
| Stable |
| Two-phase |
| Boom-bust |
| Gradual increases |
| Stable, recent increases |
| Stable, recent declines |
| Justification |
|---|
| see Fig. 11 (Ficha gatuzo, p11). |
Inter-annual variability in historical effort
| Answered |
|---|
| Not variable (less than 20% inter-annual change (IAC)) |
| Variable (maximum IAC between 20% to 50%) |
| Highly variable (maximum IAC between 50% and 100%) |
| Justification |
|---|
| See Fig 11 (ficha gatuzo, p11) |
Historical fishing efficiency changes
| Answered |
|---|
| Declining by 2-3% pa (halves every 25-35 years) |
| Declining by 1-2% pa (halves every 35-70 years) |
| Stable -1% to 1% pa (may halve/double every 70 years) |
| Increasing by 1-2% pa (doubles every 35-70 years) |
| Increasing by 2-3% pa (doubles every 25-35 years) |
| Justification |
|---|
| Increasing fishing efficiency changes (Fig 15, Perez et al., 2011, INIDEP INF TEC 79) for two vessel types (I and II) but not for type III. Many factors show p value 0.001 (vessel type x year, year x Area) |
Future fishing efficiency changes
| Answered |
|---|
| Declining by 2-3% pa (halves every 25-35 years) |
| Declining by 1-2% pa (halves every 35-70 years) |
| Stable -1% to 1% pa (may halve/double every 70 years) |
| Increasing by 1-2% pa (doubles every 35-70 years) |
| Increasing by 2-3% pa (doubles every 25-35 years) |
| Justification |
|---|
| Perez et al., 2011, INIDEP INF TEC 79 (p10) suggest a higher targeting towards gatuzo during the last years (see Fig 4) |
Length at maturity
| Answered |
|---|
| Very small (0.4 < LM < 0.5) |
| Small (0.5 < LM < 0.6) |
| Moderate (0.6 < LM < 0.7) |
| Moderate to large (0.7 < LM < 0.8) |
| Large (0.8 < LM < 0.9) |
| Justification |
|---|
|
56-72 cm /Linf 87cm TL = 0.86 (see Table 3, Ficha-gatuzo, p3). La longitud de primera madurez calculada para machos y hembras fue de 59 y 60 cm de LT, respectivamente las cuales resultaron menores a las estimadas por Menni et al. (1986), quienes obtuvieron valores de 60 cm para los machos y 62 cm para las hembras. La LT50 para ambos sexos, obtenida por Cousseau y colaboradores fue de 59 cm, ligeramente superior a la estimada para la campaña de invierno de 1993 (57 cm) (Díaz de Astarloa et al., 1997). Oddone et al., (2005) calcularon la LT50 para machos en 59 cm teniendo en cuenta que esta estimación corresponde a adultos con claspers calcificados listos para la cópula y 72 cm para hembras. En la Tabla 3 se presenta un resumen comparado de las diferentes estimaciones de talla de madurez para la especie. The narrownose smooth-hound (Mustelus schmitti) is a small shark in the family Triakidae that attains a maximum total length (TL) of 110 cm (Menni, 1985). Growth slows down in subsequent years, and, according to our results, length at first maturity (546 and 563 mm TL for males and females respectively; Colautti et al., 2010) is reached at an age of 7.61 years for females and 6.79 years for males. |
Selectivity of small fish
| Answered |
|---|
| Very small (0.1 < S < 0.2) |
| Small (0.2 < S < 0.4) |
| Half asymptotic length (0.4 < S < 0.6) |
| Large (0.6 < S < 0.8) |
| Very large (0.8 < S < 0.9) |
| Justification |
|---|
| No information was found about fishing selectivity, |
Selectivity of large fish
| Answered |
|---|
| Asymptotic selectivity (SL = 1) |
| Declining selectivity with length (0.75 < SL < 1) |
| Dome-shaped selectivity (0.25 < SL < 0.75) |
| Strong dome-shaped selectivity (SL < 0.25) |
| Justification |
|---|
| No justification was provided |
Discard rate
| Answered |
|---|
| Low (DR < 1%) |
| Low - moderate (1% < DR < 10%) |
| Moderate (10% < DR < 30%) |
| Moderate - high (30% < DR < 50%) |
| High (50% < DR < 70%) |
| Justification |
|---|
| the Argentinian catches are sub-estimated due to discarding in the hake fishery (by-catch) mainly before 2006 (Perez et al 2011, INIDEP INF TEC, p3, 5) |
Post-release mortality rate
| Answered |
|---|
| Low (PRM < 5%) |
| Low - moderate (5% < PRM < 25%) |
| Moderate (25% < PRM < 50%) |
| Moderate - high (50% < PRM < 75%) |
| High (75% < PRM < 95%) |
| Almost all die (95% < PRM < 100%) |
| Justification |
|---|
| Between November 2010 and December 2011, 2,471 individuals over 50 cm in total length were tagged, with type DART tags. Until December 2012, it was possible to recover 42 tags (1.70%) (Perez et al 2014). Esto indicaría además de una gran capacidad de natación de la especie, un buen estado general de los ejemplares marcados, por lo menos en el corto plazo. En ninguno de los ejemplares recapturados se detectó a simple vista, escaras o heridas en el sector de inserción de la marca. Estos resultados coinciden con lo señalado para otras especies de tiburones (Kohler and Turner, 2001). Los dos casos restantes correspondieron a reportes realizados por pescadores recreacionale (Perez et al 2014) |
Recruitment variability
| Answered |
|---|
| Very low (less than 20% inter-annual changes (IAC)) |
| Low (max IAC of between 20% and 60%) |
| Moderate (max IAC of between 60% and 120%) |
| High (max IAC of between 120% and 180%) |
| Very high (max IAC greater than 180%) |
| Justification |
|---|
| There is a high relationship between stock size and recruitment in sharks |
Size of an existing MPA
| Answered |
|---|
| None |
| Small (A < 5%) |
| Small-moderate (5% < A < 10%) |
| Moderate (10% < A < 20%) |
| Large (20% < A < 30%) |
| Very large (30% < A < 40%) |
| Huge (40% < A < 50%) |
| Justification |
|---|
| No justification was provided |
Spatial mixing (movement) in/out of existing MPA
| Answered |
|---|
| Very low (P < 1%) |
| Low (1% < P < 5%) |
| Moderate (5% < P < 10%) |
| High (10% < P < 20%) |
| Fully mixed |
| Justification |
|---|
| No justification was provided |
Size of a future potential MPA
| Answered |
|---|
| None |
| Small (A < 5%) |
| Small-moderate (5% < A < 10%) |
| Moderate (10% < A < 20%) |
| Large (20% < A < 30%) |
| Very large (30% < A < 40%) |
| Huge (40% < A < 50%) |
| Justification |
|---|
| No justification was provided |
Spatial mixing (movement) in/out of future potential MPA
| Answered |
|---|
| Very low (P < 1%) |
| Low (1% < P < 5%) |
| Moderate (5% < P < 10%) |
| High (10% < P < 20%) |
| Fully mixed |
| Justification |
|---|
| No justification was provided |
Initial stock depletion
| Answered |
|---|
| Very low (0.1 < D1 < 0.15) |
| Low (0.15 < D1 < 0.3) |
| Moderate (0.3 < D < 0.5) |
| High (0.5 < D1) |
| Asymptotic unfished levels (D1 = 1) |
| Justification |
|---|
| Fishery starts in before 1960. Stock assessment model starts in 1992. La pesquería argentina de gatuzo registra desembarques importantes la década de 1960 (>8.000 t), superando en 1973 las 9.000 y alcanzando en 1988 un pico de 13.500 t (CTMFM) |
Management Characteristics
Types of fishery management that are possible
| Answered |
|---|
| TAC (Total Allowable Catch): a catch limit |
| TAE (Total Allowable Effort): an effort limit |
| Size limit |
| Time-area closures (a marine reserve) |
| Justification |
|---|
|
1. Describe what, if any, current management measures are used to constrain catch/effort. Luego de valorar las distintas series de abundancia disponibles y de evaluar el comportamiento de los distintos modelos y ajustes el GT acordó utilizar, -a fin de describir las variaciones en la biomasa poblacional de gatuzo, estimar las capturas biológicamente aceptables (CBA) para 2017 y realizar las proyecciones considerando distintos escenarios de explotación-, el modelo logístico de biomasa excedente de Schaefer, ajustando sus parámetros por inferencia Bayesiana utilizando la serie de CPUE nominal en días, correspondiente a la flota argentina, para el período 1992-2016 (see Table 4, ficha-gatuzo, p8) 2. Describe historical management measures, if any. no records of previous TACs since 2016. 3. Describe main strengths and weaknesses of current monitoring and enforcement capacity. No information is provided. 4. Describe and reference any legal/policy requirements for management, monitoring and enforcement. Management based on MSY reference points and depletion levels. |
TAC offset: consistent overages/underages
| Answered |
|---|
| Large underages (40% - 70% of recommended) |
| Underages (70% - 90% of recommended) |
| Slight underages (90% - 100% of recommended) |
| Taken exactly (95% - 105% of recommended) |
| Slight overages (100% - 110% of recommended) |
| Overages (110% - 150% of recommended) |
| Large overages (150% - 200% of recommended) |
| Justification |
|---|
| No information is provided in the documentation but it is relatively important species after hake, squid, flatfish and abadejo (CTMFM 2017) |