1 About this document
This is a prototype of an automatic report that documents how the user specified the operating model and their various justifications.
2 Introduction
This MERA questionnaire was population primarily from a recent stock assessment of tiger flathead (referred to as ‘the assessment’ herein):
Day Jemery (2016) Tiger flathead (Neoplatycephalus richardsoni) stock assessment based on data up to 2015. Technical report presented at SERAG, Hobart, 24 November 2016.
https://drive.google.com/open?id=18kPzoKFMqTsErnPN3tyS3q32wDK5uNw4
- 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.
(from the assessment) “Tiger flathead have been caught commercially in the south eastern region of Australia since the development of the trawl fishery in 1915… Historical records (e.g. Fairbridge, 1948; Allen, 1989; Klaer, 2005) show that steam trawlers caught tiger flathead from 1915 to about 1960. A Danish seine trawl fishery developed in the 1930s (Allen, 1989) and continues to the present day. Modern diesel trawling commenced in the 1970s”.
- Describe the stock’s ecosystem functions, dependencies, and habitat types.
(from the assessment) “[Tiger flathead] are endemic to Australian waters and are caught mainly on the continental shelf and upper slope waters from northern NSW to Tasmania and through Bass Strait”
- Provide all relevant reference materials, such as assessments, research, and other analysis.
Day (2016) referenced above.
A fully specified OMx (DLMtool, MSEtool) operating model was also specified from the stock synthesis assessment and is available here:
https://drive.google.com/open?id=1PshBHUTtniuFyw_yUZq_B57VfrE__Fbp
This includes some details not present in the assessment report (Day 2016)
3 Fishery Characteristics
3.1 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 |
|---|
| The assessment document (page 27) states a base-case assumption of M = 0.27 per year |
3.2 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 |
|---|
| The assessment (Figure 16, page 40) estimates SSB relative to unfished of between 0.3 and 0.5 (95% CI) with a mean estimate of 0.43. |
3.3 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 |
|---|
| Steepness estimates from the assessment (Table 19, page 45) ranged from 0.61 to 0.75. |
3.4 Historical effort pattern
| Answered |
|---|
| Stable |
| Two-phase |
| Boom-bust |
| Gradual increases |
| Stable, recent increases |
| Stable, recent declines |
| Justification |
|---|
|
The stock assessment (once converted to an OM) provides a noise, approximately 2-phase effort pattern with an initial peak around 1960, a decline to half peak levels in 1980 and an increase to a recent asymptote (roughly equal to historical maximums) in 2000. Here is the pattern in historical fishing effort from the assessment (here effort is an index of fishing mortality rate with a mean of 1 over the time-series): https://drive.google.com/open?id=1Hk6yoLiE8sgPwuhqDXt3elVl86W0uoco |
3.5 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 |
|---|
|
The variable option best approximates the historical effort pattern: https://drive.google.com/open?id=1Hk6yoLiE8sgPwuhqDXt3elVl86W0uoco |
3.6 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 |
|---|
|
The variable option best approximates the historical effort pattern: https://drive.google.com/open?id=1Hk6yoLiE8sgPwuhqDXt3elVl86W0uoco |
3.7 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 |
|---|
| Since historical effort (previous question) is calculated from the assessment F trend, catchability is assumed to be approximately stable. |
3.8 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 |
|---|
| The assessment considered fish 50% mature at 30cm which is 54% of asymptotic length. |
3.9 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 |
|---|
| The operating model based on the ripped stock assessment (https://drive.google.com/open?id=1PshBHUTtniuFyw_yUZq_B57VfrE__Fbp) reveals a combined (all fleet) selectivity that is 50% around 32 cm (58% of asymptotic length) for all historical years. |
3.10 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 |
|---|
| The combined (all fleet) selectivity was asymptotic for all historical years. |
3.11 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 |
|---|
| Discard rate was calculated from the current catch fractions. Seiners and Eastern Trawl made up equal shares of current catches at (around 45%), the remaining 10% going to the Tasman trawl. Given discard rates of 4.5%, 14.8% and 0.4% (respectively) this corresponds to a total discard rate of 8.7%. |
3.12 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 |
|---|
| Since trawling and seining make almost all of the catch, post-release mortality rate is assumed to be near 100%. |
3.13 Recruitment variability
| Answered |
|---|
| Very low (less than 10% 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 |
|---|
| Recruitment variability was well approximated by selection ‘Moderate’: https://drive.google.com/open?id=1SwzDuk1qHeyvkHMpM5r-_gV1iQwoSYzN |
3.14 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 |
|---|
| We assume there have been no historical spatial closures |
3.15 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 |
|---|
| The fully mixed scenario further reduces historical MPA impacts consistent with a ‘no MPA’ scenario. |
3.16 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 |
|---|
| For demonstration purposes we assume a modest MPA of around 10-20% for testing the efficacy of future closures. |
3.17 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 |
|---|
| In order to see any impact we assume we have been smart in our MPA selection and that mixing is not too great out of this area (so there is some chance of success). |
3.18 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 |
|---|
| The assessment assumes the stock is unfished in 1915. |
4 Management Characteristics
4.1 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. Current management is by TAC control. 2. Describe historical management measures, if any. Historical TACs are listed from 2006 onwards in the assessment document. 3. Describe main strengths and weaknesses of current monitoring and enforcement capacity. No details provided in the assessment document. 4. Describe and reference any legal/policy requirements for management, monitoring and enforcement. No details provide in the assessment document. |
4.2 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 |
|---|
|
Recent TAC adherence has been on average slightly higher than specified: https://drive.google.com/open?id=1zqaYgs1a6OI8xkY_kZ47M6tLQAN7sdlz |
4.3 TAC implementation variability
| Answered |
|---|
| Constant (V < 1%) |
| Not variable (1% < V < 5%) |
| Low variability (5% < V < 10%) |
| Variable (10% < V < 20%) |
| Highly variable (20% < V < 40%) |
| Justification |
|---|
|
The variability in TAC adherence has been quite low with a CV under 10%: https://drive.google.com/open?id=1zqaYgs1a6OI8xkY_kZ47M6tLQAN7sdlz |
4.4 TAE 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 |
|---|
| Although TACs are currently enforced we assume similar characteristics for hypothetical TAEs |
4.5 TAE implementation variability
| Answered |
|---|
| Constant (V < 1%) |
| Not variable (1% < V < 5%) |
| Low variability (5% < V < 10%) |
| Variable (10% < V < 20%) |
| Highly variable (20% < V < 40%) |
| Justification |
|---|
| Although TACs are currently enforced we assume similar characteristics for hypothetical TAEs |
4.6 Size limit offset: consistent overages/underages
| Answered |
|---|
| Much smaller (40% - 70% of recommended) |
| Smaller (70% - 90% of recommended) |
| Slightly smaller (90% - 100% of recommended) |
| Taken exactly (95% - 105% of recommended) |
| Slightly larger (100% - 110% of recommended) |
| Larger (110% - 150% of recommended) |
| Much larger (150% - 200% of recommended) |
| Justification |
|---|
| Although TACs are currently enforced we assume similar violation (somewhat below) a hypothetical minimum size limit. |
4.7 Size limit implementation variability
| Answered |
|---|
| Constant (V < 1%) |
| Not variable (1% < V < 5%) |
| Low variability (5% < V < 10%) |
| Variable (10% < V < 20%) |
| Highly variable (20% < V < 40%) |
| Justification |
|---|
| Although TACs are currently enforced we assume similar variability around a hypothetical minimum size limit. |
5 Data Characteristics
5.1 Available data types
| Answered |
|---|
| Historical annual catches (from unfished) |
| Recent annual catches (at least 5 recent years) |
| Historical relative abundance index (from unfished) |
| Recent relative abundance index (at least 5 recent years) |
| Fishing effort |
| Size composition (length samples) |
| Age composition (age samples) |
| Growth (growth parameters) |
| Absolute biomass survey |
| Justification |
|---|
|
1. Provide the time series (specify years, if possible) that exist for catch, effort, and CPUE/abundance indices. The assessment document provides a figure showing the duration and quality of the various available data: https://drive.google.com/open?id=1P8RRKYYJgJj7ERXMwC71qcNksfYU6u1R 2. Describe how these data collected (e.g., log books, dealer reporting, observers). Coming soon! 3. Describe what types of sampling programs and methodologies exist for data collection, including the time-series of available sampling data and quality. Coming soon! 4. Describe all sources of uncertainty in the status, biology, life history and data sources of the fishery. Include links to documentation, reports. Coming soon! |
5.2 Catch reporting bias
| Answered |
|---|
| Strong under-reporting (30% - 50%) |
| Under-reporting (10% - 30%) |
| Slight under-reporting (less than 10%) |
| Reported accurately (+/- 5%) |
| Slight over-reporting (less than 10%) |
| Justification |
|---|
| Catches are assumed to be reported accurately. |
5.3 Hyperstability in indices
| Answered |
|---|
| Strong hyperdepletion (2 < Beta < 3) |
| Hyperdepletion (1.25 < Beta < 2) |
| Proportional (0.8 < Beta < 1.25) |
| Hyperstability (0.5 < Beta < 0.8) |
| Strong hyperstability (0.33 < Beta < 0.5) |
| Justification |
|---|
| Since commercial CPUE are being used we assume that the standardization is not perfect and that covariates of targeting may not be fully corrected for, leading to the possibility of hyperstability in indices. |
5.4 Available data types
| Answered |
|---|
| Perfect |
| Good (accurate and precise) |
| Data moderate (some what inaccurate and imprecise) |
| Data poor (inaccurate and imprecise) |
| Justification |
|---|
| This is a data-rich assessed species that serves as an archetypal stock for the testing of various management procedures from data rich to data poor. The data are considered to be of good quality relative to most fisheries. |
6 Version Notes
The package is subject to ongoing testing. If you find a bug or a problem please send a report to t.carruthers@oceans.ubc.ca so that it can be fixed!
shiny-2019-04-17-18:30:44
copyright (c) NRDC 2019