This litigation concerns the fate of a cargo of urea shipped from Romania to Nicaragua in 1974. The owner of the urea, appellant Banco Nacional De Nicaragua ("Banco Nacional"), filed suit against the insurer of the cargo, appellee Argonaut Insurance Company ("Argonaut"), alleging that a large quantity of the urea had been lost or damaged on the voyage or during the unloading of the vessel. Argonaut disagreed, arguing at trial that no loss had occurred or, alternatively, that any loss occurred after the period of coverage had ended. Siding with Argonaut, the jury to which the case was tried returned a defense verdict. The district judge entered judgment accordingly.

Banco Nacional appeals, raising three points of error. First, Banco Nacional argues that the district judge, in his instruction to the jury, erroneously placed upon Banco Nacional the burden of proving that the alleged loss of urea occurred within the policy period. Second, appellant argues that there is insufficient evidence to support the jury verdict, and therefore Banco Nacional is entitled to either a judgment notwithstanding the verdict or a new trial. Third, Banco Nacional raises an evidentiary point. We find no reversible error in the proceedings below and therefore affirm the judgment of the district court.

The M/V JAGAT PADMINI set sail from Constanza, Romania, on October 4, 1974, carrying Banco Nacional's cargo of 12,500 metric tons of urea packaged in 250,000 50-kilogram bags. The urea was in good condition when the voyage began, and the vessel issued a clean bill of lading. The JAGAT PADMINI encountered rough seas on the voyage, and the captain of the vessel filed a notice of protest because of the bad weather. The ship arrived in Porto Somoza, Nicaragua, on October 28, 1974, and unloading commenced on October 30, 1974.

There is no dispute that many of the bags containing urea were torn or broken on the voyage. As a large quantity of urea was loose in the hold, the process of unloading the ship was somewhat more difficult than in the normal case. The unloading of the vessel was completed on November 28, 1974.

There is considerable dispute regarding the quantity of urea unloaded at port. Customs documents indicate that over 192,000 bags were received in good condition, the equivalent of 18,000 bags were received in bulk, 27,000 bags were received damaged, and 12,921 bags were missing. Argonaut challenged the accuracy of these records at trial. More specifically, it argued that some urea was placed in the warehouse at Porto Somoza without first being weighed, and therefore the Customs figures for bulk urea understated the actual amount of urea unloaded. On this issue, the evidence was mixed. Regarding the cause of the alleged loss of urea, Banco Nacional produced several theories to explain the loss, but no substantial proof regarding what caused the alleged losses was adduced at trial.

The all-risks insurance policy written by Argonaut covered Banco Nacional against all risks of physical harm to its cargo of urea caused by any external force, subject to certain exceptions. The policy contained a "warehouse-to-warehouse" clause. Under this clause, the policy coverage extended from the time the urea left the warehouse in Romania until it was discharged from the vessel at Porto Somoza, Nicaragua.

Sometime after the unloading, Banco Nacional filed a claim with Argonaut for the alleged losses of urea. Argonaut, after investigating the claim, denied that a loss occurred and refused to make payment on the claim. Banco Nacional then filed suit.

Banco Nacional argues that the district court's instruction to the jury improperly placed upon Banco Nacional the burden of proving that the alleged loss of urea occurred within the period that the policy was in force.1 Argonaut argues that this burden is properly part of the insured's prima facie case of proving a loss. Both parties base their arguments on the decision of the former Fifth Circuit2 in Morrison Grain Company, Inc. v. Utica Mutual Insurance Company, 632 F.2d 424 (5th Cir. 1980).3 We agree with Argonaut that the jury instructions were proper under Morrison. Morrison involved a claim under an all-risks marine insurance policy with respect to urea lost during shipment from Romania to Mississippi. A large quantity of that urea had dissolved during the voyage,4 and urea was also lost or damaged at sea or on discharge due to breakage of the container bags. Morrison, the insured, recovered at trial, and the insurer appealed, claiming that Morrison should have had the burden of proving that the loss was not caused by an inherent vice or defect (i.e., defective packaging) which existed prior to the period of coverage. The Morrison court rejected this argument, holding that the defense of inherent vice or defect constituted "an exception to coverage the burden of proving which properly lies with the insurer under an 'all-risks' policy." Id. at 431 (footnote omitted). The court then specified the allocation of the respective burdens of proof applicable in a suit under an all-risks policy:

Morrison, the insured, had the initial burden of proving a loss by showing that the cargo of urea was in good condition when the policy attached and in damaged condition when unloaded from the vessel. The burden then shifted to Insurer, to show exception to coverage.

Id. In other words, Morrison held that the burden was on the insured to show that some loss occurred during the period of coverage, i.e., that the goods unloaded were not in the same condition or quantity as those loaded onto the vessel.

In the instant case, there was significant dispute at trial regarding whether a loss had in fact occurred and whether any actual loss had occurred within the policy period. Banco Nacional, in effect, argues that all it need show as part of its prima facie case is that it lost urea at some unspecified time, not necessarily during the voyage or discharge. Proof that the loss occurred outside the policy period would be an exception to coverage under Banco Nacional's theory, and thus the burden under Morrison would be on Argonaut.

We reject this argument. The plaintiff in a suit under an all-risks insurance policy must show a relevant loss in order to invoke the policy, and proof that the loss occurred within the policy period is part and parcel of that showing of a loss. Rather than being an exception to coverage, as an inherent vice or defect would be, proof that a loss occurred within the policy period is a predicate to the application of the policy. Thus, as Morrison indicates, the burden of proving that the loss occurred during the policy period is properly on the insured, Banco Nacional.5 The instructions in this case inform the jury that Banco Nacional must carry that burden, and that the jury could not speculate on the issue of whether the losses occurred within or after the policy period. We therefore conclude that the jury instructions in this case properly allocated the respective burdens of proof.

Banco Nacional argues that the trial judge erred in failing to direct a verdict in favor of Banco Nacional on the issue of coverage. It advances two grounds to support this argument. First, Banco Nacional argues that the evidence is wholly insufficient to support the jury verdict. Second, it argues that because all of the affirmative defenses raised by Argonaut were stricken by the trial court, the trial judge was required to direct a verdict in favor of Banco Nacional. Banco Nacional also argues that the trial judge erred in failing to grant its motion for a new trial on the ground that the verdict was against the great weight of the evidence. We reject these arguments.

The test for determining whether a party is entitled to a directed verdict or judgment notwithstanding the verdict is set forth in Boeing Co. v. Shipman, 411 F.2d 365, 374-75 (5th Cir. 1969) (en banc). We "should consider all of the evidence-not just that evidence which supports the non-mover's case-but in the light and with all reasonable inferences most favorable to the party opposed to the motion." Id. at 374. It is proper to submit a case to the jury "if there is substantial evidence opposed to the motions, that is, evidence of such quality and weight that reasonable and fair-minded men in the exercise of impartial judgment might reach different conclusions." Id. However, the court may not determine questions of credibility or weigh conflicting evidence or inferences. Id. at 375.

After reviewing the record before us, we conclude that there was substantial evidence supporting the jury verdict, and that therefore the district court properly denied appellant's motions for a directed verdict and for a judgment notwithstanding the verdict. We reach this conclusion because of the evidence in the record supporting the theory that the Customs figures did not accurately reflect the amount of urea unloaded from the JAGAT PADMINI. The testimony of the bank's own employee, Mr. Duarte, who served as Banco Nacional's representative at the port during the discharge operation, indicated that the bulk urea that was placed in the warehouses at dockside was loaded directly into the warehouses without first being weighed. Mr. Duarte further testified that the only time that the urea was weighed was when it left the port on a truck. The record indicated that much of the bulk urea in the warehouses at port remained there for several months after the discharge operation was completed. The weighings of the bulk urea which formed the basis of the Customs figures, however, were completed by November 30, 1974, two days after the unloading was complete. The bank records reflecting the amounts of urea weighed as it left the port were not produced at trial. Thus, Mr. Duarte's testimony would support a conclusion by the jury that a large quantity of urea had escaped weighing by the Customs officials, and that the Customs document does not accurately reflect the amount of urea received in port. Although there is other testimony in the record which conflicts with that of Mr. Duarte, we of course may not weigh this conflicting evidence or make credibility choices among the witnesses. We therefore conclude that there is substantial evidence to support the jury's verdict in favor of Argonaut.6

We find no merit in Banco Nacional's argument that it is entitled to a directed verdict because the district court struck the affirmative defenses raised by Argonaut. As indicated above, there is evidence in the record to support a conclusion by the jury that Banco Nacional had not carried its burden of proving a loss within the policy period. This provides ample basis for the denial of a directed verdict. In light of this, the fact that the trial judge had stricken the affirmative defenses raised by Argonaut is irrelevant, since the jury could have concluded that Banco Nacional had not proven its case.

Likewise, we must reject Banco Nacional's argument that the trial judge erroneously denied its motion for a new trial on the grounds that the verdict was against the great weight of the evidence. A motion for a new trial on weight of the evidence grounds is committed to the sound discretion of the district court, and the district court's denial of such a motion will be reversed by the court of appeals only where the record indicates an abuse of that discretion. Ellis v. Chevron U.S.A. Inc., 650 F.2d 94, 97 (5th Cir. 1981); 6A Moore's Federal Practice, P 59.08(5) (1979). In this case, we find that the district court did not abuse its discretion in denying Banco Nacional's motion for a new trial.

The final point raised on appeal by Banco Nacional concerns the decision of the district judge to admit into evidence, over Banco Nacional's objection, certain testimony relating to Banco Nacional's duty to select the type of packaging for the urea shipment. Apparently, Banco Nacional had not specified the type of bag that should be used for the shipment. Banco Nacional objected at trial to the introduction of this testimony on the ground that it was irrelevant. The district judge had previously stricken Argonaut's affirmative defenses to the effect that the bags were inherently defective,7 and that the negligence of Banco Nacional had caused the loss. After a conference outside of the hearing of the jury, the district judge admitted this evidence on the ground that it was relevant to the issue of whether Banco Nacional had made reasonable efforts to mitigate its damages. Banco Nacional made no request that the district judge instruct the jury that the evidence was admitted only for this limited purpose, and no such instruction was given. Banco Nacional now argues that the admission of this testimony was prejudicial error.

We conclude that the admission of this testimony was not prejudicial error. Although Argonaut does not advance any persuasive theory to demonstrate that this evidence is at all relevant to the issue of mitigation, we conclude that any error in introducing this testimony was harmless. The lack of relevance of this evidence on the question of mitigation does not produce a ground for reversal. The jury never considered the issue of damages, but returned a verdict for the defendant on the issue of liability. In order for the jury to have considered this evidence on the issue of mitigation, they would have had to first return a verdict for the plaintiff on the liability issue. The jury was instructed that if they then found a failure to mitigate, they must specify on the verdict the amount of damages that resulted from the failure to mitigate. The verdict for the defendant, then, clearly indicates that the jury never reached the issue of mitigation. Because the jury did not consider this issue, the admission of this evidence could not have improperly affected the jury with respect to the issue of damages.

Banco Nacional also argues that this evidence was prejudicial on the issue of liability. They argue that the jury could have considered this evidence and other evidence related to the defective nature of the bags, and returned a verdict of no liability because of Banco Nacional's failure to select proper packaging. We reject this argument. First, the trial judge specifically instructed the jury that the negligence of Banco Nacional or any inherent defect in the bags would not be a defense to the coverage under the policy. Moreover, Banco Nacional failed to request a limiting instruction, to which it clearly would have been entitled, that the jury was not to consider this evidence with respect to any issue of coverage in the case. Such a limiting instruction, coupled with the instruction to the jury mentioned above, would have no doubt cured any error in the admission of this evidence with respect to the issue of liability. Therefore, we conclude on the basis of this record that no reversible error occurred.8

For the foregoing reasons, the judgment of the district court is

AFFIRMED.