Where is the science
Alfredo
Attached is my letter to the BFAR
Director which critiques the multimillion peso Mangrove Project
featured in 2 recent articles in the MAP Newsletter.
Director which critiques the multimillion peso Mangrove Project
featured in 2 recent articles in the MAP Newsletter.
Jurgenne
——————————————————————————————
Atty. Asis Perez
Director, Bureau of Fisheries and Aquatic Resources
Fax 02-929-8074
Dear Director Perez
The Department of Agriculture and the Bureau of Fisheries
and Aquatic Resources (BFAR) are to be commended for your pro-environment and
pro-poor Mangrove Project with funding of ~PhP280 million (Philippine Daily
Inquirer, 31 Oct. 2011 and 30 Dec. 2011). Given the substantial amount of
public funds, may I share the following observations and concerns pertaining to
the three project components.
and Aquatic Resources (BFAR) are to be commended for your pro-environment and
pro-poor Mangrove Project with funding of ~PhP280 million (Philippine Daily
Inquirer, 31 Oct. 2011 and 30 Dec. 2011). Given the substantial amount of
public funds, may I share the following observations and concerns pertaining to
the three project components.
A. Mangrove Planting – This targets 11 million propagules
covering 3,667 hectares for 2012 (of a total 100 million propagules over the
next 3 years), and rightfully gives priority to abandoned government-leased (or
FLA) fishponds. Though sociopolitically problematic, these ponds are the
ecologically correct sites for rehabilitation as they were former mangrove
forests. In contrast, past mangrove rehabilitation programs focused on
noncontroversial, open access seafront sites – planting by convenience, not by
ecology. These less than favorable sites yield low survival, and mangroves will
suffer even more if planted where coastlines are vulnerable to sea level rise
due to Climate Change.
covering 3,667 hectares for 2012 (of a total 100 million propagules over the
next 3 years), and rightfully gives priority to abandoned government-leased (or
FLA) fishponds. Though sociopolitically problematic, these ponds are the
ecologically correct sites for rehabilitation as they were former mangrove
forests. In contrast, past mangrove rehabilitation programs focused on
noncontroversial, open access seafront sites – planting by convenience, not by
ecology. These less than favorable sites yield low survival, and mangroves will
suffer even more if planted where coastlines are vulnerable to sea level rise
due to Climate Change.
Hence, it would be prudent to reserve most of the budget
allocated for mangrove rehabilitation to reversion of abandoned ponds, and use
only a small fraction for seafront planting, unlike past programs. The BFAR
project should support moves to streamline the cancellation process for
abandoned, unutilized and underdevelopedFLA
ponds and their reversion to DENR. To date, very few AUU government ponds have
been cancelled, and these few ponds are declared open and available to new
applicants, instead of reverting to mangroves as mandated by law.
allocated for mangrove rehabilitation to reversion of abandoned ponds, and use
only a small fraction for seafront planting, unlike past programs. The BFAR
project should support moves to streamline the cancellation process for
abandoned, unutilized and underdeveloped
ponds and their reversion to DENR. To date, very few AUU government ponds have
been cancelled, and these few ponds are declared open and available to new
applicants, instead of reverting to mangroves as mandated by law.
Moreover, sustainable aquaculture requires 4 hectares of
mangroves for every hectare of pond (Saenger et al, 1983). Only 248,000 ha of
Philippine mangroves remain while culture ponds have increased to 230,000 ha,
giving a ~1: 1 mangrove-pond ratio, which means we have a long way to go to
restore the required 4:1 ratio. Our best bet in increasing mangrove hectarage
is by reverting tens of thousands of hectares of abandoned ponds, and not the
ecologically difficult rehabilitation of seafronts.
mangroves for every hectare of pond (Saenger et al, 1983). Only 248,000 ha of
Philippine mangroves remain while culture ponds have increased to 230,000 ha,
giving a ~1: 1 mangrove-pond ratio, which means we have a long way to go to
restore the required 4:1 ratio. Our best bet in increasing mangrove hectarage
is by reverting tens of thousands of hectares of abandoned ponds, and not the
ecologically difficult rehabilitation of seafronts.
B. Aquasilviculture – Described as mangrove farming, the
reported objective of this component is to grow fish, shrimp and other aquatic
crops in the newly planted mangrove areas. Following are some relevant
considerations, based on research at the SEAFDEC Aquaculture Department.
reported objective of this component is to grow fish, shrimp and other aquatic
crops in the newly planted mangrove areas. Following are some relevant
considerations, based on research at the SEAFDEC Aquaculture Department.
Aquasilviculture combines cultured crops with mangrove trees
either in the same stand, or in separate ponds.
Whereas mangroves need the regular ebb and flooding of sea water,
aquatic species like shrimp and fish require a permanent water column,
therefore the trees and animals are incompatible. Following the first model,
only mud crabs which can withstand exposure during low tide can be farmed
inside mangrove netpens – provided the trees are fully grown and not the newly
planted seedlings envisioned in the BFAR proposal, as crabs will consume the
tender leaves of the latter (Primavera et al, 2009). Moreover, canals that
provide shelter in the low tide should be dug in the center of the pen away
from the net enclosures because the crabs can burrow deep in the mud and escape
to the outside.
either in the same stand, or in separate ponds.
Whereas mangroves need the regular ebb and flooding of sea water,
aquatic species like shrimp and fish require a permanent water column,
therefore the trees and animals are incompatible. Following the first model,
only mud crabs which can withstand exposure during low tide can be farmed
inside mangrove netpens – provided the trees are fully grown and not the newly
planted seedlings envisioned in the BFAR proposal, as crabs will consume the
tender leaves of the latter (Primavera et al, 2009). Moreover, canals that
provide shelter in the low tide should be dug in the center of the pen away
from the net enclosures because the crabs can burrow deep in the mud and escape
to the outside.
The 2nd Aquasilviculture model features mangroves as
biofilters for separate intensive shrimp/fish ponds, requiring 2-8 hectares and
up to 20 hectares, respectively, of mangroves to process the nitrogen and
phosphorus effluents produced by one hectare of adjacent pond (Primavera et al,
2007). These ratios may even be higher than the 4:1 required for aquaculture
sustainability and environmental health.
biofilters for separate intensive shrimp/fish ponds, requiring 2-8 hectares and
up to 20 hectares, respectively, of mangroves to process the nitrogen and
phosphorus effluents produced by one hectare of adjacent pond (Primavera et al,
2007). These ratios may even be higher than the 4:1 required for aquaculture
sustainability and environmental health.
C. Multispecies Hatcheries – These simple, community-based
facilities are to serve as “lying-in centers” where gravid females of crabs and
other high-value species will be allowed to spawn and/or hatch their eggs, and
young larvae released in adjacent mangroves.
facilities are to serve as “lying-in centers” where gravid females of crabs and
other high-value species will be allowed to spawn and/or hatch their eggs, and
young larvae released in adjacent mangroves.
However, newly-hatched larvae of marine crabs, shrimps and
fish need the full salinity (30-35 parts per thousand or ppt) of near/offshore
waters to complete their larval stages. Therefore they cannot be released in
intertidal mangrove waterways which often have fluctuating salinity levels that
go down to 5-10 ppt. Even if salinity remains high enough for survival, the
vulnerable larvae will still need to fend off predators and learn how to
forage, hence their mortality rates are expected to be high. For such planned
releases to contribute significantly to wild fish and shellfish populations,
the scientific guidelines of Stock Enhancement – an established discipline of
fisheries – will need to be applied.
fish need the full salinity (30-35 parts per thousand or ppt) of near/offshore
waters to complete their larval stages. Therefore they cannot be released in
intertidal mangrove waterways which often have fluctuating salinity levels that
go down to 5-10 ppt. Even if salinity remains high enough for survival, the
vulnerable larvae will still need to fend off predators and learn how to
forage, hence their mortality rates are expected to be high. For such planned
releases to contribute significantly to wild fish and shellfish populations,
the scientific guidelines of Stock Enhancement – an established discipline of
fisheries – will need to be applied.
Protocols not only for Stock Enhancement, but also for the
other BFAR Project components (which have yet to be spelled out), must be
science-based to improve the chances for success of this multimillion peso
project. As far as I know, the BFAR has yet to officially consult the
aquaculture and mangrove scientists of the country.
other BFAR Project components (which have yet to be spelled out), must be
science-based to improve the chances for success of this multimillion peso
project. As far as I know, the BFAR has yet to officially consult the
aquaculture and mangrove scientists of the country.
J.H. Primavera, Ph.D.
Pew Fellow in Marine Conservation
Scientist Emerita
SEAFDEC
Aquaculture Department
Aquaculture Department
Tigbauan, Iloilo
Project Manager, ZSL Community-Based Mangrove
Rehabilitation
Project in thePhilippines
Project in the
Quezon St.