General overview of the world’s fish stocks
The following figures were taken from the United Nations Food and Agricultural Organization's report "Review of the State of World Marine Fisheries Resources".
Of all fish species currently being harvested commercially;
3% are underexploited
20% are moderately exploited
52% are fully exploited
17% are overexploited
7% are depleted
1% are recovering from depletion
Where, underexploited, undeveloped or new fishery means it is believed to have a significant potential for expansion in total production,
Moderately exploited means it is exploited with a low level of fishing effort and it is believed to have some limited potential for expansion in total production;
Fully exploited means the fishery is operating at or close to an optimal yield level, with no expected room for further expansion;
Overexploited means the fishery is being exploited at above a level which is believed to be sustainable in the long term, with no potential room for further expansion and a higher risk of stock depletion/collapse;
Depleted means catches are well below historical levels, irrespective of the amount of fishing effort exerted;
Recovering means catches are again increasing after having been depleted.
REMEMBER LIMIT YOUR CATCH, DON’T CATCH YOUR LIMIT!
Reference paper link - https://www.fao.org/docrep/015/i2389e/i2389e.pdf
Individuals only reach sexual maturity at three years of age, roughly 40cms. These fish can live up to 20 years and can reach a size of ±90cms. Adult fish utilise estuaries heavily, as a constant supply of food is present in these systems. They feed up heavily during the onset of spring to build up weight before they spawn in surf zones adjacent to river mouths during October-December. The small grunter larvae then actively swim back up into the rivers, where they use the eelgrass beds and shallow marshes as nursery habitats to grow up in relative safety.
Current size limit is 40cm, bag limit 5 pppd. The stock of this species is vulnerable to over exploitation due to its high estuarine dependence and residency during both the juvenile and adult phases of the lifecycle.
How to catch grunter
These fish can be targeted using mudprawn, sandprawn, chokka, sardine, bloodworm and tapeworm. Many artificial anglers target them successfully over shallow mudbanks using fly and surface lures.
Individuals only reach sexual maturity after 6 years, at roughly 90cm-1m in length. These fish can live up to ages of around 42, reaching lengths of ±2m. Adult fish are heavily dependent on river systems as areas with easy access to bait fish and other prey items. These fish spawn offshore in large aggregations (Griffifths, 1996). Spawning takes place in the nearshore environment, from August to November in KwaZulu/Natal, and from October to January in the Southern and South-Eastern Cape regions. A large proportion of the adult population migrates to KwaZulu/Natal to spawn, although spawning may continue on their return to the Cape (Griffifths, 1996). Early juveniles of 20-30 mm (less than 4 weeks) are recruited into turbid estuaries along the entire East Coast (Griffifths, 1996). They remain in the upper regions of the estuaries until they grow to about 150 mm (Griffifths, 1996). Juveniles larger than 150 mm are found in estuaries and in the surf zone. Fish less than 1m generally do not migrate long distances, remaining as separate allopatric populations (occurring in separate non-overlapping geographical areas) around their natal estuaries until they reach maturity (Griffifths, 1996). It is postulated that the protection from predation afforded by estuarine and surfzone nursery areas has allowed Kob to evolve a life history with a large size at maturity, thereby "preadapting" it to a migratory life-style. This life history, including late maturity, the use of estuarine and surf-zone nursery areas, and a migratory adult population which forms concentrated spawning aggregations, is particularly vulnerable to the activities of man.
Reference paper link - https://www.tandfonline.com/doi/pdf/10.2989/025776196784158653
How to catch kob
These fish can be targeted using mudprawn, sandprawn, chokka, sardine, bloodworm, live bait or octopus. Many artificial anglers target them successfully using drop shot, bucktails or plastics such as paddle tails and fluke minnows. The key with artificial is to locate good structure, such as drop offs to deeper water, or craggy rocky drop offs where these ambush predators can hide.
Individuals only mature at 6 years of age, at roughly 65cm in length. These fish can live up to 30 years reaching a maximum size of roughly 140cm. Spawning appears to be localized on the Transkei and Eastern Cape coasts during a short period in late winter (Bennet, 1993). Small juveniles (< 5 cm) enter estuarine nursery grounds along the Cape coast between September and November, remaining there for at least their first year of life before re-entering the marine environment (Bennet, 1993). The post-estuarine juveniles (> 15 cm) are semi-resident in the surf zone of sandy and mixed shores for about five years until maturing, when they commence annual migrations (Bennet, 1993). During autumn and early winter these mature fish migrate eastwards to near the north-eastern limit of their distributional range, to spawn during late winter (Bennet, 1993). The return migration takes place during spring and large numbers of mature fish arrive in the South-Western Cape during summer (Bennet, 1993). The high degree of estuarine dependence, the confinement of juveniles and subadults to the surf-zone, the large size at maturation and the predictable aggregations of mature individuals in particular areas are considered to render white steenbras particularly vulnerable to estuarine degradation and exploitation by fishermen (Bennet, 1993).
Reference paper link - https://www.tandfonline.com/doi/pdf/10.2989/025776193784287257
How to catch Steenbras
These fish can be targeted using mudprawn, sandprawn, chokka, sardine, bloodworm, octopus, tapeworm, or white mussel. Many artificial anglers target them successfully using drop shot or surface lures when fishing for other species such as kob or grunter. This fish is excellent fun on light tackle, displaying explosive runs.
Individuals reach sexual maturity at 3-4 years of age at roughly 60 cm in length. Data collected by the ORI’s Cooperative Fish Tagging Project (ORI-CFTP) suggests that adult leervis undertake an annual migration from Cape waters to KZN during winter. There is strong evidence to suggest that the migration is associated with spawning and possibly aided by food availability during the annual sardine run.
Information gathered from the recapturing of previously tagged and released fish indicates that adult leervis are more vulnerable in KZN waters due to the increased fishing effort during the sardine run and the seasonal targeting of this species. The high catchability, and hence vulnerability, of this voracious predator in KZN waters during the migration lead to large-scale catches by many unscrupulous recreational anglers. There were many reports of daily bag limits being exceeded and also illicit selling by recreational users. If repeated, the consequences of such actions, without management intervention, could negatively impact the sustainability of this important coastal fishery species.
How to catch Leerie
These fish can be targeted using live bait, however if this method is used it is best to use circle hooks, as J-hooks can really damage gills or internal organs. Many artificial anglers target them successfully using drop shot, bucktails, plastics, fly or surface lures. This fish is excellent fun on light tackle, displaying explosive runs and is a clean fighter. The best place to focus on are areas holding large numbers of baitfish such as mullet, olive grunter (piggy) or cape stumpnose. Keep an eye open for explosions on the surface where leeries are chasing bait, and work those areas with artificials. If there are no visible signs of leerie, focus on sandy drop offs to deeper water, or areas with strong currents where bait fish may become disorientated.
When practicing catch and release angling
Heavier tackle and single hooks with a squashed/flattened barb are far better than ultra-light line and barbed hooks/trebles. Circle hooks with flattened barbs are excellent for releasing fish.
Fish that are landed or boated should be treated with great care in order to avoid loss of scales and injury through flapping. Place the fish on a wet sack or towel and cover the head (eyes) with it, turning the fish belly-up usually calms it down considerably. Keeping a wet dish cloth/rag handy, i.e. attached to your fishing bucket, works well for this purpose.
Fish Research Projects
The Breede River is one of the healthiest estuaries in South Africa. Many people visit the river on an annual basis for a bit of fishing. Fish populations all over the world are either classified as collapsed or on the brink of collapsing. For this reason the monitoring of all fish species in the Breede River is of great importance. Currently there are two continuous fish monitoring projects run by the LBRCT, other projects coordinated by other organisations do occur and the LBRCT provides assistance where possible.
During your time spent fishing on the rocky shore, river banks or off your boat on the river, you may be interviewed by LBRCT staff. You will be asked questions about what time you started fishing, what bait you are using, what hook size you are using, the fish you are targeting and whether or not you have caught anything yet? Whilst these questions may all seem like a way to for staff to sniff out your tips and tricks - they actually an informative method to establish what is happening to the fish populations in the estuary and determine the fishing pressure.
Ultimately what we are trying to determine if there is any fluctuation in the effort it takes for anglers to catch fish. If we consider the amount of time it takes anglers to catch fish, and monitor this over a long time (long-term monitoring), with thousands and thousands of interviews, we can calculate what the fish populations are doing over time, and seasonally. This is called Catch Per Unit Effort or CPUE. So, after a bunch of number crunching, we can directly correspond the effort it takes an angler to catch a fish, to the population in the estuary. As an example, if 30 years ago it took half an hour on average, for an angler to catch a grunter, and today it takes say an hour, we can conclude that the fish populations are under strain. This may be due to a host of factors such as overfishing and seasonal fluctuations and these must all be considered.
You may also see staff sitting on LBRCT vessels fishing. This is not staff neglecting their duties on the river. In fact, it is quite the contrary. This is the LBRCT staff gathering further data on fish stocks in the river, and contributing to another CPUE data set. Changes in the CPUE are inferred to signify changes to the target species' true abundance. A decreasing CPUE indicates overexploitation, while an unchanging CPUE indicates sustainable harvesting. We also use this opportunity as a means to contribute to the ORI fish tagging programme. Where tagged fish are released to fight another day, and thus give information on growth rates and fish movement patterns.
CPUE has a number of advantages over other methods of measuring abundance. It does not interfere with routine harvesting operations, and data are easily collected. The data are also relatively easy to analyse, even for non-specialists. This means that decisions about stock management can also be made by the people doing the harvesting.
Essentially the overall outcome of the research is to indicate estuarine health regarding fish species. If catches are still regular and fish sizes are large one can figure that the fish stocks are looking safe just as an example. So next time you see the LBRCT staff approaching you with a clipboard, don’t panic just get ready to add your little bit to the conservation of the fish you so enjoy.
The LBRCT will be releasing a catch return form that can be completed and submitted by any fisherman willing to help conservation. This form mirrors the fish stat form but allows anybody to collect data. The data on this form is vital and a real chance to get involved in the ichthyofaunal conservation of the Breede.
Twice a year the LBRCT assists the Department of Agriculture, Forestry and Fisheries (DAFF) to sample the estuary fish. This is done twice a year, once in winter and again in summer. Two different methods are used; one is the use of trek nets to collect the juvenile and small fish species, the other is a gill net with different mesh sizes to sample the larger fish found deeper in the estuary.
All the fish caught are measured and recorded and then released back into the system. This is highly valuable research because it gives one a snapshot in time of what fish are where and in what numbers they are being found.
Data on the DAFF fish survey netting programme is available upon request from DAFF.
This project is run by the South African Shark Conservancy (SASC). The LBRCT is active in the monitoring of these sharks and are on call to SASC when possible. The Zambezi shark has been in our system for many years but has only been researched by scientists recently. This is the furthest South that these sharks have been recorded and as such there is very little known about them.
For further information on this project, please visit the SASC website: https://www.sharkconservancy.org/
Often ORI tags are brought in or reported to the LBRCT. The LBRCT collects this data and makes sure that ORI gets the most accurate data possible. The tagging project makes use of voluntary members of the public to tag and collect data. This valuable scientific data provides information about movement patterns, growth rates, mortality rates and population dynamics of our important linefish species. This data in turn can inform management decisions for sustainable use of our linefish.
For further information on this project, please visit the ORI website: : http://www.oritag.org.za/login?mode=register
How to join ORI TAG and join the fish tagging community
If you are interested in becoming a member of the ORI Cooperative Fish Tagging Project then please contact the Tagging Officer (Email: email@example.com / Tel: 031 328 8159 / Cell: 079 529 0711).
How to report a capture
To report the capture of a fish with a tag in it, please email firstname.lastname@example.org or call/sms/whatsapp 079 529 0711. The following details are required:
- TAG NUMBER (e.g. D153654 or A145879)
- LENGTH (total, precaudal , fork etc.)
- LOCALITY CAUGHT
- DATE CAUGHT (DD/MM/YYYY)
- RELEASED (Y/N)
- ANGLER DETAILS (name and email).