Conservation

[Brenden]

hi guys i dont know how to post attachements so i just copy and paste some interesting articles written by Dr Mike Allen

Myths about spawning bass busted
Bass spawning season is upon us across
much of the country. I’ve heard quite a few
myths about bass spawning activities over
the years, and for some of these myths we
have scientific evidence that may shed light.
Let’s summarize the science about bass
spawning behavior.
Bass spawn primarily on hard, sandy
bottom.
This myth is absolutely not true. Scientists
around the country have found bass
nesting on a wide range of bottom types. In
lakes with lots of aquatic plants, fish often
nest on tangled roots on the bottom, which
is the most common spawning habitat in
many Florida lakes. Nests around the country
also are also common on rock, gravel,
and even on submerged stumps found
in deeper water! A recent study by Zach
Lawson and colleagues from the University
of Wisconsin showed that largemouth
bass preferred to nest either on or very
near woody debris. In lakes that had large
numbers of docks and little woody cover,
largemouth bass built nests in deeper water
where woody debris could be found. This
suggested that bass preferred to nest near
woody structure if it was available. Bass
clearly have the capability to take advantage
of a wide range of habitat for spawning, and
they don’t require a hard sandy bottom.
Each female spawns with only one male.
In fishery biology, the term “total spawners”
means that fish lay all of their eggs at
once during each spawning season. Many
trout and salmon species are total spawners.
Largemouth bass are what we call “batch
spawners”, which means that females deposit
their eggs in batches over the spawning season
and not all at once. Batch spawners mature
their eggs in small batches and spread
them over multiple spawning events each
year. Genetic studies have confirmed that
female bass spawn with multiple males
across a given spawning season.
Males build one nest per year.
Evidence from Florida indicates that male
bass can, in some cases, build more than one
nest per year and protect the eggs and larvae
until they disperse, which is the point where
parental care ceases. This process is a lot of
work for male bass, because protecting the
eggs from predators is nearly a full-time job,
leaving little time for feeding activities. However,
my graduate student Stephanie Shaw has
found that in some lakes, the average male
raises at least two broods per year. The long
spawning season in the southern states makes
this feasible. It’s less likely that males can successfully
raise more than one brood in the
northern states, where total spawning duration
may be only a period of two to three weeks.
Fish spawn only in shallow water.
Bass nests have been confirmed with photos
as deep as at least 20 feet of water, and
the depth of nests is influenced by available
spawning habitat and water temperatures.
In general, we find the shallowest bass nests
early in the season, where water temperatures
are warmest in the upper water column.
As the season progresses, bass nests
are found in progressively deeper water. The
average depth of bass nests in the Florida
lakes we are studying is about 4 feet, with
nests commonly found as shallow as 1 foot
and as deep as 10 feet. The Wisconsin study
mentioned earlier found that bass nested
in deeper water if there was little cover,
and shallower water if the shoreline lacked
woody debris. That study found bass nests
as shallow as 6 inches and as deep as about 5
feet in six Wisconsin lakes.
In summary, all of these myths can be dispelled,
at least to some degree, with evidence
seen in field studies. The take home message
is that bass are extremely adaptable and able
to spawn effectively across a wide range of
habitat conditions and depths.
If you have other myths for consideration
in future columns, feel free to drop me an
email at <!-- e --><a href="mailto:msal@ufl.edu">msal@ufl.edu</a><!-- e -->.
Mike S. Allen
Bass Times_changingthehooks_treblehook.indd 1 4/2/12 1:05 PM