This material is for TYBSc students learning in Mumbai University, India. The course is Applied component Fishery Biology

1. Prof S D Rathod
B N Bandodkar College of Science
Thane, Maharashtra, India

2. LifeBuoy

3. Life saving raft and boat
Inflatable Boat Inflatable Yatch

4. Flash signal light High
speed rescue-boat

5. Rocket Flares and horns
signaling

6. Radio devices
Nautilus Lifeline GPS GPS Personal Locator
Marine Radio for Divers or Beacon is the perfect
Boaters solution

7. Radio Devices

8. Remote Sensing

9. Satellite System
The open ocean
provides a tough
work
environment, it
is vital that
personnel and
vessels stay in
touch at all
times & help in
improvement of
crew moral and
entertainment.

11. Oceanographic Instruments

12. Sonar fish finders

13. Eco-ranging

14. Fish finding

16. Nansen’s reversing bottle
 Nansen bottles, invented by the
Norwegian oceanographer Fridtjof
Nansen, are cylindrical containers that
sample sea temperature and salinity.
 The bottle, more precisely a metal or
plastic cylinder, is lowered on a cable
into the ocean, and when it has reached
the required depth, a brass weight called
a "messenger" is dropped down the
cable. When the weight reaches the
bottle, the impact tips the bottle upside
down and trips a spring-loaded valve at
the end, trapping the water sample
inside. The bottle and sample are then
retrieved by hauling in the cable.

17. Peterson’s grab
 Device is used by aquatic and marine
biologists. Since 1930 the Petersen
grab has been used in fresh water for
collecting macroscopic fauna in sand,
gravel, marl, clay or clay combinations.
If used in salt water, it must be painted
for protection. Since it has been widely
used over 6 decades, it is ideal for
comparing samples with data collected
previously by a Petersen grab.
 Vent holes permit water to flow through
while the grab is being lowered,
minimizing diagonal movement as well
as reducing the frontal shock wave
generated by descent. Jaws close
clamshell fashion

18. Dredges
 Similar to a beam trawl, a dredge
consists of a rugged triangular steel
frame and tooth-bearing bar, behind
which a mat of linked steel rings is
secured.
 A heavy netting cover joins the sides
and back of this mat to form a bag in
which the catch is retained. Shellfish
are raked out of sand or gravel and
swept into the bag.
 Several dredges are towed together
from a tow bar and larger vessels
generally tow two bars, one from each
side of the vessel. In suction dredges
and hydraulic dredges, water is shot
into sediments and displaced shellfish
are collected in a mesh bag
(hydraulic) or sucked to the surface
through a pipe (suction).

19. Scallop Dredge
 Scallop dredging involves using
a dredge that consists of a
metal frame with spring-loaded
teeth to which a chain-mesh
bag is attached.
 The dredge is towed over
seabed habitats, where the
teeth rake the seabed disturbing
the scallops. This gear is
extremely robust and can be
used over much harder grounds
than traditional trawls. As a
consequence, scallop dredges
can severely damage other
seabed organisms and habitats.

20. Clamshell bucket dredge
 The clamshell bucket dredge, also known as
the grab dredge, is the most commonly used
mechanical dredge. the world over. This
dredge may consist simply of a crane
mounted on a spud barge, although most
bucket dredges have a crane/barge system
specifically designed and constructed for
dredging.
 A bucket dredge is operated similarly to a
land-based crane and bucket. The crane
operator drops the bucket through the water
column, allowing it to sink into the sediment
on contact. The loaded bucket is then lifted,
causing the jaws to close, and raised through
the water column. Once above the water
surface, the operator swings the bucket over
the receiving container (usually a barge) and
lowers the bucket to release its load. The
bucket dredge usually leaves an irregular,
cratered sediment surface (Herbich and
Brahme 1991).

21. Other dredges
 Dredge and power
shovel : Dredges
 There are two types of
dredge: the mechanically
operated and hydraulically
operated. Mechanical
dredges, which are similar
to land-based excavating
machines, were the first to
be developed and can be
classified as dipper,
grapple, or ladder dredges.

22. Thank You